ELECTRONIC LOCOMOTIVE CONTROL SYSTEM IIA Caterpillar

Troubleshooting

Usage:

Introduction

Troubleshooting can be difficult. To make a repair to a problem, make reference to the cause and correction.

This list of problems, causes and corrections, will only give an indication of where a possible problem can be, and what repairs are needed. Normally, more or other repair work is needed beyond the recommendation in the list.

Remember that a problem is not normally caused only by one part, but by the relation of one part with other parts. This list can not give all possible problems and corrections. The service personnel must find the problem and its source, then make the necessary repairs.

Refer to Systems Operation Testing And Adjusting, 3500 Locomotive Engines, SENR4637 for mechanical troubleshooting of the engine.

Troubleshooting Problems

6.1: Engine Will Not Crank When Start Switch Activated

Probable Cause

* Locomotive Controls Not Set Correctly.

* Low Battery Voltage.

* Mechanical Seizure In Engine/Driven Equipment.

* Defective Starter Motor/Solenoid.

* Defective Magnetic Switch.

* Defective Locomotive Wiring.

* Fault In The Shutdown Relay Logic Box.

Locomotive Controls Not Set Correctly

All locomotives have interlocks to inhibit starting if the controls are not set correctly (the run/isolate switch must be in the isolate position). Check all such interlocks and set them correctly.

Low Battery Voltage

Check the battery voltage with and without the start switch energized.

Nominal voltage with switch deactivated should be 64 Volts DC.

Minimum voltage with switch activated should be 28 Volts DC.

NOTE: The relays used in the start and shutdown logic can have a drop-out voltage as high as 28 Volts DC and require 48 Volts DC to energize.

If either of the above voltage readings are low, check the condition of the battery. Charge or replace as necessary.

Mechanical Seizure In Engine Or Driven Equipment

If the "6.1.3: Low Battery Voltage" tests are normal but show a significant drop when activating the start switch, this indicates that both starters are properly engaged and that the starter windings are indeed pulling high current levels out of the battery.

This indicates that there is a mechanical seizure in either the starter motors, engine or driven equipment. Investigate and repair.

Defective Starter Motor/Solenoid/Magnetic Switch

1. Observe the indicator window on the START RELAY to determine whether it is being energized when the start switch is activated.

If it is not being energized proceed to Step 12.

2. If it is being energized, check the starter motor magnetic switches (SMMS1 and SMMS2) while the start relay is energized (refer to "4.13: Wiring Diagrams" for details).

The two mag (SMMS) switches have their coils connected in series with an interconnecting strap. Check the voltage across the series connected coils. It should be at nominal battery voltage (64 Volts) with the start relay energized.

If it is not at nominal battery voltage with the start relay energized, proceed to Step 16.

3. If it is at nominal battery voltage with the start relay energized, the wiring must be studied to determine which starter motor is SM1 and which is SM2; also which mag switch is SMMS1 and which is SMMS2.

Check the voltage at the "bat" connection on the solenoid of SM1 with respect to the "s" connection on the solenoid of SM1 with the start relay de-energized. This voltage should be at approximately 50 percent of battery voltage.

If it is not there is a problem in one of the starter motors. Proceed to Step 11.

4. Check the voltage at the "bat" connection on the solenoid of SM1 with respect to the "s" connection on the solenoid of SM1 with the start relay energized. This voltage should be less than one volt.

If it is not there is a problem in SMMS1, replace SMMS1.

5. If SMMS1 is OK:

Check the voltage at the "bat" connection on the solenoid of SM2 with respect to the "s" connection on the solenoid of SM2 with the start relay de-energized. This voltage should be at approximately 50 percent of battery voltage.

If it is not there is a problem in one of the starter motors. Proceed to Step 11.

6. Check the voltage at the "bat" connection on the solenoid of SM2 with respect to the "s" connection on the solenoid of SM2 with the start relay energized. This voltage should be less than one volt.

If it is not there is a problem in SMMS2, replace SMMS2.

NOTE: If the above tests indicate that SMMS1 and SMMS2 are both OK, the problem must be in one of the starter motors. At least one, if not both main solenoid contacts are not being pulled in.

7. Check the voltage at the "bat" connection on the solenoid of SM1 with respect to the "mtr" connection on the solenoid of SM1 with the start relay de-energized. This voltage should be at approximately 50 percent of battery voltage.

If it is not there is a problem in one of the starter motors. Proceed to Step 11.

8. Check the voltage at the "bat" connection on the solenoid of SM1 with respect to the "mtr" connection on the solenoid of SM1 with the start relay energized. This voltage should be less than one volt.

If this test fails there is a problem in the solenoid of SM1; replace SM1.

9. Check the voltage at the "bat" connection on the solenoid of SM2 with respect to the "mtr" connection on the solenoid of SM2 with the start relay de-energized. This voltage should be at approximately 50 percent of battery voltage.

If it is not there is a problem in one of the starter motors. Proceed to Step 11.

10. Check the voltage at the "bat" connection on the solenoid of SM2 with respect to the "mtr" connection on the solenoid of SM2 with the start relay energized. This voltage should be less than one volt.

If this test fails there is a problem in the solenoid of SM2; replace SM2.

NOTE: If in following the above procedures to this point a defective component has not been identified, one of the procedures was performed incorrectly. Repeat starting from Step 1.

11. There must be a problem with one of the starter motors, or one of the starter motor solenoids.

Disconnect the starter motors and solenoid connections from the battery and mag switches and, for each motor, check the impedances of the following:

Pull-in coils.

Hold-in coils.

Motor windings.

NOTE: Specifications, 3500 Locomotive Engines, SENR4636 contains the specifications for the motors. Replace or repair as necessary.

12. Note at this point Step 1 failed and the start relay is not being energized with the start switch energized.

Check the voltage on TB397-R12 with respect to TB395-R1 in the remote mounted junction box with the engine at rest. This should be at nominal battery voltage (64 Volts DC).

If it is not, the problem could be either in the box wiring, or in the speed switch.

13. Check the voltage on Electronic Speed (Overspeed) Switch terminal 11 with respect to TB395-R1. This should be at nominal battery voltage (64 Volts DC).

If it is not, there is a problem in the junction box wiring. Refer to "4.13: Wiring Diagrams" to troubleshoot the wiring.

14. Check the voltage on Electronic Speed (Overspeed) Switch terminal 12 with respect to TB395-R1 with the engine at rest. This should be at nominal battery voltage (64 Volts DC).

If it is, there is a problem in the junction box wiring between ESS terminal 12 and TB397-R12. Refer to "4.13: Wiring Diagrams" to troubleshoot the wiring.

15. If Step 14 voltage is not nominal battery voltage (64 Volts DC), there is a problem in the switch. Replace and calibrate according to "8.14: Electronic Speed (Overspeed) Switch and 8.16: Electronic Speed (Overspeed) Switch".

16. Note at this point Step 2 failed and the start relay is being energized but the magnetic switches are not.

Check the voltage on TB395-L1 with respect to TB395-R1. This should be at nominal battery voltage (64 Volts DC).

If it is not, there is a problem in the junction box wiring. Refer to "4.13: Wiring Diagrams" to troubleshoot the wiring.

17. If Step 16 is at nominal battery voltage (64 Volts DC), there is a problem in the locomotive wiring between TB397-L1, start relay contacts, start switch and the magnetic switches. Refer to the "4.13: Wiring Diagrams" to troubleshoot the wiring.

6.2: Engine Cranks But Will Not Start

Probable Cause

* Tripped Air Intake.

* Notch Lever In Shutdown.

* Electronic Governor System Diagnostic Code.

* Incorrect Rack Sensor Calibration.

* Electrical System Problem

* Shutdown System Problem.

* Locomotive Wiring Problem.

* Electronic Governing System Problem.

Tripped Intake Air Shutoff

Visually inspect intake air shutoffs and reset if tripped. If this symptom continues to occur on subsequent start attempts, refer to "6.16: Engine Spontaneously Shuts Down".

Notch Lever In Shutdown Position

Visually inspect notch lever and set it to the normal idle position if it is in the shutdown position.

Electronic Governor Diagnostic Codes

Check the status of the electronic governor's diagnostic LED's (upper one and lower four LED's). The three diagnostic codes that would most likely cause the engine to not start while cranking are:

Code 1: Failed Rack Sensor or Rack Sensor Harness.

Code 2: Failed Speed Sensor or Speed Sensor Harness.

Code 4: Failed Personality Module.

If there are any diagnostic codes being displayed refer to "Section 7: Diagnostic Code Troubleshooting" for detailed troubleshooting before proceeding with the rest of this procedure.

Incorrect Calibration Of Rack Position Sensor

Check the calibration of the rack position sensor that is part of the electronic governor system according to "8.15: Rack Sensor Calibration" before proceeding with the rest of this procedure.

Electrical System Problem

The are three electrical systems that could be causing this defect:

Shutdown System.

Locomotive Wiring.

Electronic Governor System.

It is important that the "6.2.6.1: Shutdown System Fault, 6.2.6.2: Locomotive Wiring, and 6.2.6.3: Electronic Governor System Problem" are completed in order without skipping any sections.

6.2.6.1: Shutdown System Fault

1. Visually monitor indicator flag on SR1 relay in remote mounted shutdown box while cranking the engine. This should turn from green to red immediately when the engine starts to crank.

2. If the SR1 indicator flag stays green, refer to "6.2.7: Shutdown System Troubleshooting" to troubleshoot the shutdown system.

3. If the SR1 indicator flag changes to red, proceed to "6.2.6.2: Locomotive Wiring" and check the locomotive wiring.

6.2.6.2: Locomotive Wiring

1. Disconnect the two wires (that are part of the locomotive electrical system) to TB392-L1 and TB392-L2 at the electronic governor mounting group (refer to "4.13: Wiring Diagrams" to identify the location of the electronic governor mounting group).

2. Monitor the impedance between these two wires prior to, and during cranking. Prior to cranking the impedance should be infinite (open circuit) and during cranking it should be between 25 and 40 ohms.

3. If Step 2 impedance measurements give the wrong values, or the impedance stays at infinity during cranking, there is a problem either in the rack actuator or in the wiring between either TB392-L1 and TB254-B3 or between TB392-L2 and TB254-B4 (refer to "4.13: Wiring Diagrams" for details).

To electrically check the rack actuator, remove the lid to the electrical harness pull-thru box mounted on the right hand side of the engine front housing to the rear of the rack actuator and disconnect the red and black rack actuator wires from the terminal block inside the box (TB254-B3 & TB254-B4 respectively). Measure the impedance between these two wires. It should be between 25 and 40 ohms.

If the actuator impedance is incorrect, replace the rack actuator. Refer to "8.29: Actuator Check".

If the actuator impedance is correct, investigate the problem in the locomotive's electrical system.

If Step 2 impedance measurements are correct, it is possible (but unlikely) that the connections are transposed in the locomotive wiring and the drive current to the rack actuator is reversed. This is most likely if the locomotive is being commissioned.

The connections between the electronic governor and the rack actuator are made via the locomotive wiring and the factory wired engine harness. The connection paths are as follows:

Refer to "4.13: Wiring Diagrams" for full details. Investigate and verify that the actuator is connected properly. If so, proceed to "6.2.6.3: Electronic Governor System Problem". If not, correct the connections and start the engine.

6.2.6.3: Electronic Governor System Problem

Monitor status of LED display on electronic governor and attempt to start the engine. Crank engine for 15 to 20 seconds. Prior to cranking, the only LED that should be on is the "shutdown" status LED. During cranking this LED should go off above 96 rpm.

If the shutdown LED stays on above 96 rpm proceed to "7.4.4: Permanent Defect".

If the shutdown LED goes out above 96 rpm the cranking rack position must be measured as follows:

Install and calibrate digital rack sensor. The 8T1000 Electronic Position Indicator Group is available for calibrating the rack sensor.

NOTE: An accessory kit (Probe Contactor Point Group 6V6042) is available that contains a selection of different length extensions for the 8T1002 probe. The correct extension is the same for all 3500 engines. The correct extension should be chosen so that the 8T1001 indicator will properly display shut-off rack position as well as the maximum mechanical position. All 3500 engines require the indicator to be set up to display increasing rack with a retracting sensor.

Remove the calibration pin and crank the engine and note what position the rack goes to. Refer to Personality Module Settings, SENR5187 for the correct position for the particular personality module fitted to the locomotive.

The rack calibrate position referred to in Personality Module Settings, SENR5187 is a nominal position for software reference only. The actual rack position is the maximum mechanical rack position that can be obtained from the engine mounted specification plate.

If the rack starting position is incorrect proceed to "6.2.6.3.1: Rack Starting Position Incorrect". If the rack starting position is correct proceed to "6.2.6.3.2: Rack Starting Position Correct".

6.2.6.3.1: Rack Starting Position Incorrect

If the rack starting position is incorrect the problem could be in one of the following:

Rack Position Sensor Harness (customer): refer to "4.13: Wiring Diagrams" to determine any loose connections, open circuits or short circuits (including those to engine block or locomotive chassis).

Rack Position Sensor Harness (factory engine): refer to "4.13: Wiring Diagrams" to determine any loose connections, open circuits or short circuits (including those to engine block or locomotive chassis).

Rack Position Sensor Harness (factory electronic governor mounting group): refer to "4.12 Installation Diagrams (Diagram 22)" to determine any loose connections, open circuits or short circuits (including those to engine block or locomotive chassis).

Non Linear Rack Position Sensor: Refer to "8.9: Rack Position Sensor and 8.15: Rack Position Sensor" to replace and recalibrate the rack position sensor.

6.2.6.3.2: Rack Starting Position Correct

If the rack starting position is correct, there is no problem in the governor system. The problem must be in the fuel system:

Poor quality fuel.

Water in the fuel.

No fuel to the injectors.

Low fuel pressure.

Wrong injection timing.

Refer to Systems Operation Testing And Adjusting, 3500 Locomotive Engines, SENR4637 for investigating the fuel system.

Shutdown System Troubleshooting

NOTE: Refer to "4.13: Wiring Diagrams".

1. Monitor the voltage on TB395-L2. It should be nominal battery voltage.

If not, there is a break in the connection between TB395-L1 and TB395-L2. Repair the problem.

2. If Step 1 passes, monitor the voltage on TB395-L7 and activate the start switch. With the start switch activated this voltage should nominal battery voltage.

If not, there is a break in the locomotive wiring in the start switch/diode connections to TB395-L2 and TB395-L7, or there is a defect in the start switch or diode. Repair the problem.

3. If Step 2 passes, monitor the voltage on SR1-Y and activate the start switch. The voltage reading should switch to nominal battery voltage as the start switch is activated.

If it stays at ZERO Volts DC, there is a break in the connections between TB395-L7 and SR1-Y. Repair the problem.

4. If Step 3 passes, monitor the voltage on SR1-Z and activate the start switch. The voltage reading should step from zero to less than ten Volts DC as the start switch is activated.

If the reading stays at ZERO Volts DC, there is a defect in relay SR1. Replace the relay.

If the reading is OK, there is a defect in relay SR1. Replace the relay.

5. If Step 4 reading jumps to nominal battery voltage, monitor the voltage on TB396-L10 and activate the start switch. The reading will step to nominal battery voltage or stay at ZERO Volts.

If it stays at zero there is a break in the connections between SR1-Z and TB396-L10. Repair the problem.

6. If Step 5 result steps to nominal battery voltage, there is a problem in customer wiring between TB396-L10 and TB252-B1 or a problem in the engine wiring harness.

Monitor the voltage on TB252-B1 and activate the start switch. If it stays at ZERO Volts DC there is a break in the connections between TB396-L10 and TB252-B1. Repair the problem.

7. If Step 6 result steps to nominal battery voltage there is a problem in the engine wiring harness or the intake air shutoff solenoid.

On 3508 and 3512 engines, check the continuity between each end of the intake air shutoff solenoid and TB252-B1 and TB252-B2. Repair any problems found.

NOTE: On 3516 engines the connections to TB352-B1 and TB251-B2 are an integral part of the solenoid.

8. Check the impedance of the intake air shutoff solenoid. Replace the solenoid if it is defective. Impedance for the intake air shutoff solenoids should be:

3508 and 3512 ... 24.8 to 30.4 ohms

3516 ... 110.4 to 129.6 ohms

6.3: Engine Overspeeds

Probable Cause

* False Overspeed Trip.

* Mechanical Binding Of Rack Linkage.

* Defective Rack Actuator.

* Locomotive Electrical Harness Fault.

* Engine Electrical Harness Fault.

* Defective Electronic Governor Box.

False Overspeed Trip

Refer to "8.21: Electronic Speed (Overspeed) Switch" to check the calibration and proper functioning of the Electronic Speed Switch in the junction box.

If necessary replace the Electronic Speed Switch. Refer to "8.14: Electronic Speed (Overspeed) Switch".

There are four other possible areas that could cause this symptom:

1. Mechanical binding of the rack linkage.

2. Defective Rack Actuator.

3. Electrical harness problem (engine and customer).

4. Defective Electronic Governor Box.

It is recommended to investigate these four areas in the order listed above. This will minimize the possible number of unnecessary overspeed shutdowns.

Mechanical Binding Of The Rack Linkage

Disconnect the mechanical link between the rack actuator lever and the rack linkage lever.

Check the rack linkage system for mechanical binding.

NOTE: With the fuel system full, it is possible for the rack linkage to appear bound up with a stationary engine. It may be necessary to vent a possible hydraulic lock in the fuel system.

If binding is not present, the linkage is OK. Check that the length of the actuator link is properly adjusted to ensure that when the linkage is at the minimum mechanical rack position, the actuator's position is within its normal dynamic range and not against its minimum mechanical position.

If the actuator link length is OK, proceed to "6.3.4: Defective Rack Actuator".

If binding is present, inspect and identify its source and repair it.

Re-connect the mechanical link between the rack actuator lever and the rack linkage lever.

Defective Rack Actuator

NOTE: The mechanical rack link should still be disconnected.

Remove the lid to the electrical harness pull-thru box mounted on the right hand side of the engine front housing to the rear of the rack actuator and disconnect the red and black rack actuator wires from the terminal block inside the box (TB254-B3 & TB254-B4). Observe the movement of the rack actuator lever while attempting to start the engine.

If the actuator lever does not move the actuator is not defective; proceed to "6.3.5: Electrical Harness Problem".

If the actuator lever moves in the increasing rack direction the actuator is defective and should be replaced. Refer to "8.29: Actuator Check".

Re-connect the red and black rack actuator wires to the terminal block and refit the lid to the electrical harness pull-thru box mounted to the rear of the rack actuator.

Re-connect the mechanical link between the rack actuator lever and the rack linkage lever.

Electrical Harness Problem

NOTE: The mechanical rack link should still be disconnected.

Refer to the appropriate locomotive prints to identify the location of the electronic governor box.

Disconnect the locomotive electrical system connections to TB392-L1 and TB392-L2.

Observe the movement of the rack actuator lever while attempting to start the engine.

If the actuator lever does not move the electronic governor box is suspect and this should be confirmed by proceeding to "6.3.6: Defective Electronic Governor Box".

If the actuator lever moves in the increasing rack direction the problem is in the electrical connections between the TB392 electronic governor and TB 254 rack actuator connections. These connections entail both customer and factory wiring. A detailed review and analysis of the locomotive prints and wiring diagrams in "Section 4: Installation" is therefore necessary to troubleshoot and repair this defect.

Re-connect the mechanical link between the rack actuator lever and the rack linkage lever.

Defective Electronic Governor Box

With everything that had been disconnected re-connected, and the manual rack shutoff lever properly manned, start the engine and observe whether the engine is governed at idle speed, or accelerates in an uncontrolled fashion.

NOTE: If necessary, use the manual rack shut off lever to shut the engine down to avoid exceeding the rated speed of the engine.

If the engine governs correctly at idle speed, something in the procedures in "6.3.2: False Overspeed Trip through 6.3.5: Electrical Harness Problem" rectified it. The Electronic Governing System is not defective.

If the engine did not govern correctly at idle speed, and continued to accelerate in an uncontrolled fashion, the Electronic Governing System is suspect.

Procedure To Confirm A Defective Electronic Goveror Box

Remove and safely tape up the locomotive system wire to TB392-L1. Start the engine and observe whether the engine is governed at idle speed, or accelerates in an uncontrolled fashion.

NOTE: If necessary, use the manual rack shut off lever to shut the engine down to avoid exceeding the rated speed of the engine.

If the engine does not start, the Electronic Governing System is defective. Replace the box according to "8.2: Main Governor Box".

Reconnect the wire to TB392-L1 and start the engine.

If the engine now accelerates in an uncontrolled fashion there is not a defect in the electronic governing system. The problem was caused by an intermittent problem. Start back at "6.3.2: False Overspeed Trip" to find the defect.

6.4: Erratic Engine Speed

Introduction

The nature of the erratic engine speed must first be determined:

* Are the speed changes random or more in the nature of a cyclic lope or instability?

* Are the speed changes smooth or jerky in the nature?

* Does it occur at all speeds or over a limited speed range?

* Does it occur under load or with no load?

* Does it occur with a cold engine or with warm engine?

NOTE: If the erratic engine speed is short, sharp, jerky speed changes this could result in the display of diagnostic codes 5 or 6 on the electronic governor system. Perform the remainder of this section and only refer to "7.7: Code 5-Rack Slew Rate Or 7.8: Code 6-Stuck Rack" to troubleshoot these diagnostic codes if the codes are continued to be displayed after the speed governing problem has been fixed.

Probable Cause

* Cold Engine Oil.

* Damping Orifice Of Rack Actuator Out Of Adjustment.

* Individual Injectors Not Synchronized.

* Rack Linkage Is Binding Or Worn With Free Play.

* Engine Misfiring.

* Engine Speed Sensor.

* Engine Speed Sensor Harness.

* Main Electronic Governor Box.

* Rack Position Feedback Sensor.

* Rack Position Feedback Sensor Harness.

* Harness Connections Carrying Rack Actuator Current.

* Engine To Generator Coupling.

* Ferrous Chips Magnetically Attracted To Speed Sensor Tip.

Cold Engine Oil

The engine speed governor algorithm is sensitive to engine oil temperature, type and viscosity. It is normal for the engine speed to cyclically lope under no load conditions with a cold engine.

Depending on how cold the engine is, the speed normally stabilizes under load.

Damping Orifice Of Rack Actuator Out Of Adjustment

The response of the EG-10P rack actuator can be adjusted by turning an adjustment screw on the side of the actuator body. Turning this screw counterclockwise speeds up the response of the actuator. Generally this will stabilize a cyclic speed lope.

NOTE: Use extreme care when turning the screw clockwise. If the screw is bottomed out, it should only be subjected to very low torque. This screw should always be at least one half turn out from its fully clockwise position.

Individual Injectors Not Synchronized

Refer to Injector Synchronization in Systems Operation Testing And Adjusting, SENR4637 for the correct procedure to calibrate and synchronize injector racks.

Rack Linkage Is Binding Or Worn

Refer to "Problem 4: Engine Speed Does Not Have Stability" in the Troubleshooting section of Systems Operation Testing And Adjusting, SENR4637 to troubleshoot this problem.

Engine Misfire

Refer to "Problem 8: Engine Misfiring Or Running Rough" in the Troubleshooting section of Systems Operation Testing And Adjusting, SENR4637 to troubleshoot this problem.

Engine Speed Sensor Harness

Usually a problem with the speed sensor harness will not allow the engine to run. If the engine can run the problem must be intermittent in nature. This will result in random, sharp or jerky speed changes rather than a cyclic lope or instability.

Refer to "4.12: Installation Diagrams (diagrams 11 thru 15)" for all the connections involved in this harness. The complexity defies a methodical, systematic procedure. The simplest and quickest method of verifying a harness problem is to fabricate a temporary harness and install it in place of the engine and locomotive harness. A direct connection should be between:

Speed Sensor Connector Pin C TB392-L6

Speed Sensor Connector Pin A TB392-L7

Speed Sensor Connector Pin B TB392-L8

If the erratic engine speed ceases with the temporary harness installed and resumes when the regular harness connections are re-connected, the problem is in the regular harness connections.

Inspect all the harness connections to determine any loose connections, frayed or damaged insulation causing intermittent open circuits or short circuits (including those to the engine block or locomotive chassis) and make any necessary repairs.

If the erratic engine speed ceases with the temporary harness installed and does not resume when the regular harness connections are re-connected, the problem is in the following areas that were disturbed during the swap:

* Speed Sensor

* Speed Sensor Connector In Regular Harness

* Fast-on Connectors In Regular Harness That Connect To TB392

Inspect the speed sensor connector and fast-on connectors for poor crimp or solder joints and make any necessary repairs. If no problems are found replace speed sensor according to "8.11: Speed Sensor".

If the erratic engine speed does not cease with the temporary harness installed the problem is not in these harness connections. Other connections that could cause erratic engine speed are in the electronic governor mounting group. Refer to "4.12: Installation Diagrams (diagram 22)" as follows:

* J2 Connector Pin 6 TB392-L6

* J2 Connector Pin 7 TB392-L7

* J2 Connector Pin 8 TB392-L8

Inspect these connections for poor crimp or solder joints and frayed or damaged insulation. Make any necessary repairs.

Engine Speed Sensor

Usually a problem with the speed sensor will not allow the engine to run. If the engine will run the problem must be intermittent in nature and will result in random and sharp or jerky speed changes rather than a cyclic lope or instability.

Refer to "8.11: Speed Sensor" to check that the air gap is set correctly.

If a defective speed sensor is responsible for the erratic engine speed, there is no way to methodically identify it as the cause. If all other possible causes have been eliminated, change the speed sensor according to "8.11: Speed Sensor".

6.4.9.1: Magnetic Chips On Speed Sensor Tip

Inspect the tip of the speed sensor and ring gear for cleanliness and absence of any magnetically attracted chip. If necessary clean up and reuse the chip.

Main Electronic Governor Box

An intermittent internal connection within the main electronic governor box can cause the same erratic engine speed as an intermittent problem in the speed sensor harness and speed sensor.

This defect is possible, but highly improbable, and cannot be methodically identified without changing the main electronic governor box.

If the troubleshooter decides to change this box, it should be changed according to "8.2: Main Governor Box".

Rack Position Feedback Sensor Harness

Since the rack sensor shares the same isolated power as the speed sensor, it is possible for a problem with the rack sensor harness connections to cause erratic engine speed in the form of random and sharp or jerky speed changes rather than a cyclic lope or instability.

* Rack Sensor Connector Pin 1 TB392-L3

* Rack Sensor Connector Pin 3 TB392-L4

* Rack Sensor Connector Pin 2 TB392-L5

If the erratic engine speed ceases with the temporary harness installed and resumes when the regular harness connections are re-connected, the problem must be in the regular harness connections.

* Rack Sensor

* Rack Sensor Connector In Regular Harness

* Fast-on Connectors In Regular Harness That Connect To TB392

Inspect the rack sensor connector and fast-on connectors for poor crimp or solder joints and make any necessary repairs. If no problems are found replace the rack sensor according to "8.9: Rack Position Sensor".

If the erratic engine speed does not cease with the temporary harness installed the problem is not in these harness connections. Other connections that could cause erratic engine speed are in the electronic governing mounting group. Refer to "4.12: Installation Diagrams (diagram 22)" as follows:

* J2 Connector Pin 3 TB392-L3

* J2 Connector Pin 4 TB392-L4

* J2 Connector Pin 5 TB392-L5

Inspect these connections for poor crimp or solder joints and frayed or damaged insulation. Make any necessary repairs.

Rack Position Sensor

There are two ways a defect in the rack sensor can result in erratic engine speed:

* An electrical problem that affects the speed sensor signal as in "6.4.11: Rack Position Feedback Sensor Harness".

* An erratic position feedback problem. This would cause the load regulation control functions to erratically control the load and be noticed as erratic engine speed (only under load).

In either even the erratic engine speed would cease if the rack position sensor were unplugged from the engine harness.

Unplug the rack position sensor from the engine harness.

If the erratic engine speed ceases, the defect was in the rack position sensor. Change the rack sensor according to "8.9: Rack Position Sensor".

Rack Actuator Drive Current Path

An intermittent internal connection in the harness connections and system connections that carry the rack actuator drive current can cause erratic engine speed.

This defect is theoretically possible, but highly improbable.

"4.12: Installation Diagrams (diagrams 11 thru 15)" show the engine harness and customer wired sections of the current path. Reference must be made to the locomotive prints to identify some of the harness details.

Add a temporary harness in place of the normal wiring between TB392-L1 and TB392-L2 and between TB254-B3 and TB254-B4.

NOTE: Exercise extreme caution when running the engine in this state since it by-passes the shutdown system. The shutdown position of the notch lever will still shut the engine down.

Run the engine and observe whether the speed is still erratic. If it is no longer erratic there is a definite problem in the rack actuator current path. Refer to "4.12: Installation Diagrams (diagrams 11 thru 15)" to troublshoot.

Rack Actuator And Oil Supply

An internal rack actuator defect or a problem with the actuator oil supply can cause erratic engine speed.

Engine To Generator Main Coupling

The two bearing traction generator has a coupling to the engine that is torsionally flexible.

Since none of the auxiliary loads are carried thru this coupling the average torque thru this coupling is essentially zero with the main traction alternator not excited.

With zero average torque thru this coupling it is possible for a problem with the coupling to be the cause of erratic engine speed at no load or at any speed. Normally this would be caused if the coupling has lost all or part of its damping grease. The erratic speed may only become evident with a warm engine.

Refer to "8.30: Generator Coupling" for the procedure to check the rotational free play of the coupling. If the free play of the coupling is excessive, contact the appropriate Caterpillar Customer Services Group.

6.5: Engine Does Not Stay Running After A Start

Probable Cause

* Operator Releasing The Start Switch Too Soon.

* Emergency Shutdown.

* Defective Auxiliary Generator.

* Non Electrical Problem (Accompanied By A Relatively Slow Engine Speed Decay Rather Than An Abrupt Engine Stop).

Operator Releasing The Start Switch Too Soon

If the engine operator is releasing the start switch too soon (before the engine reaches crank/terminate speed) the engine will shut down.

Re-start the engine and ensure the start switch is held in until after the starter motors have disengaged.

Emergency Shutdown

The shutdown logic has the following emergency shutdown features:

* Low oil pressure.

* Overspeed.

* High crankcase pressure (3516 only).

* Low coolant level.

Check the locomotive's annunciation panel for these conditions and note if any are tripped. If any are tripped, refer to the pertinent manual for the condition that is being annunciated:

Low Oil Pressure SENR4636

Overspeed "6.3: Engine Overspeeds (This section)"

High Crankcase Pressure (3516) SENR4636

Low Coolant Level SENR4636

Low Auxiliary Generator Output Voltage

The shutdown logic allows the engine to run for a nominal nine second time period above crank terminate speed with no auxiliary generator output. At the end of the nine second period, if the auxiliary generator output is not at least 48 Volts DC, the engine will shut down. This particular shutdown is not annunciated from the Caterpillar shutdown logic. A low auxiliary generator output condition is normally annunciated by the locomotive system.

Start the engine and measure the voltage on TB395-L12 with respect to TB395-R1: note the reading when the engine shuts down. If it is less than 48 Volts DC there is a problem in one of the following:

* Auxiliary generator or voltage regulator.

* Logic that inhibits the auxiliary generator excitation below starter cutout speed.

To determine where the problem is refer to "6.20: Auxiliary Generator Not Properly Excited".

Non Electrical Problem

With the above shutdown modes, the engine shuts down deliberately and abruptly. Immediately prior to shutting down, if the engine exhibits erratic running or misfiring, or a slow decay in speed, the problem is probably not electrical. Refer to "Problem 8: Engine Misfiring Or Running Rough" in the Troubleshooting section of Systems Operation, Testing And Adjusting, SENR4637 for detailed troubleshooting.

6.6: Engine Will Not Shutdown

Introduction

There are four methods of manually shutting the engine down. They are listed below in order of usage from the most commonly used (1) to the least commonly used (4) as follows:

1. Momentarily depressing one of the several normal shutdown pushbuttons distributed around the locomotive. This will open the drive current path between the electronic governor and the rack actuator.

2. Setting the notch lever to the shutdown position. This sets the desired engine speed in the electronic govenor to zero.

3. Momentarily depressing the emergency shutdown pushbutton. This will trip the intake air shut-off devices; the 3516 engines have 2, and the 3512 and 3508 engines each have one. An overspeed condition will do the same.

4. Operating the mechanical shutdown lever on the left side of the front housing of the engine. This will overrid the rack actuator and force the rack linkage to the shut-off position.

These four methods of shutting the engine down should ensure that every engine will be able to be shutdown. It should be noted that although all four methods are standard features of the Caterpillar package, not all locomotives will be equipped with items number 2 and 3.

Probable Cause

The probable cause depends on which of the four shutdown modes is inoperative:

* Normal Shutdown Pushbuttons Inoperative

* Shutdown Notch Code Inoperative

* Emergency Shutdown Pushbutton Inoperative

* Mechanical Shutdown Lever Inoperative

Mode 1-Normal Shutdown Pushbuttons Inoperative

6.6.3.1: Problem With The Shutdown System

Visually monitor the indicator flag on SR1 relay in the remote mounted shutdown box while operating, one at a time, each of the normal shutdown pushbuttons. This should turn from red to green and latch in the green position with a momentary operation of any one of the normal shutdown pushbuttons.

If the flag stays red, refer to "6.6.3.2: SR1 Problem", for detailed troubleshooting.

If the flag changes and latches to green and the engine stays running, the shutdown system is OK. The problem could still be:

* An electrical problem in the rack actuator drive current path.

* A defective rack actuator.

* A mechanical problem with the rack linkage.

Proceed directly to "6.6.3.2: SR1 Problem", to determine which of the above three causes is responsible for the problem.

If any one of the normal shutdown pushbuttons successfully shuts the engine down, the problem is in the locomotive wiring associated with those switches that are inoperative, or in the actual switches that are inoperative.

6.6.3.2: SR1 Problem

Measure the voltage at SR1-Y with respect to TB395-R1 with the engine running and one of the normal shutdown switches activated.

If this voltage is ZERO, replace SR1.

If this voltage stays at NOMINAL BATTERY VOLTAGE, refer to "4.13: Wiring Diagrams" to identify the string between TB395-L5 and SR1-Y.

After the engine has been running for more than nine seconds since reaching crank/terminate speed, the current path to energize SR1 is via SR2-2 contacts, the low water level switch, normal-stop-switch string, high crankcase pressure switch (3516 only) SR3-3 contacts, low speed oil pressure switch, high speed oil pressure switch or oil step switch contacts, diode 1, SR1-3 contacts and diode 2. For SR1 to be energized, each of these points should be at nominal battery voltage. Everything downstream of TB396-L6 should be at ZERO VOLTS with any of the normal shutdown switches activated.

Measure the voltages along this current path with the engine running and the normal stop switch activated to determine where the problem is.

6.6.3.3: Electrical Problem

To identify whether there is an electrical problem, first remove the lid to the electrical harness pull-thru box mounted on the right hand side of the engine front housing to the rear of the rack actuator. Disconnect the red and black rack actuator wires from the terminal block inside the box (TB254-B3 and TB254-B4 respectively). The engine should shut down immediately when the first wire is pulled.

If the engine does not shut down, there is mechanical binding in either the rack actuator or in the rack linkage. Proceed to "6.6.3.4: Problem With The Rack Linkage Or Actuator Binding".

If the engine shuts down, there is an electrical problem with the rack actuator drive current path.

Reconnect the rack actuator wires to TB254-B3 and TB254-B4 and re-start the engine. Identify the location of the TB392 on the locomotive prints and pull the locomotive system wire connecting to TB392-L1. The engine should shut down immediately, confirming that there is a short circuit somewhere in the locomotive wiring or the remote mounted junction box wiring has shorted contacts (across the SR1 contacts that interrupt the rack actuator drive current or SR1). Refer to "4.13: Wiring Diagrams".

6.6.3.4: Problem With The Rack Linkage Or Actuator Binding

Disconnect the rack linkage from the actuator and check each for binding. Repair damaged parts.

Mode 2-Shutdown Notch Code Inoperative

Only perform the following procedures if the shutdown notch function is the only shutdown function that is inoperative. If any of the other shutdown functions are inoperative, investigate and repair those first.

6.6.4.1: Problem With The Locomotive Wiring

With the notch lever in the shutdown position measure the voltages on the following points with respect to TB391-R3. The results should be:

If the above signals are incorrect the problem is in the locomotive electrical system. Refer to "4.12: Installation Diagrams (diagram 11)" for detailed troubleshooting of this problem.

6.6.4.2: Problem With The Electronic Governor System

If the above signals are correct the problem is in the mounting group wiring or the main electronic governing box.

Disconnect the J1 harness connector from the main electronic governing box and check the continuity between:

TB391-R4 J1/16

TB391-R5 J1/17

TB391-R6 J1/18

TB391-R7 J1/19

Also check for any damage to the connector (badly retained connector contacts that easily "push in"). Repair any problems that are found.

If no problems are found replace the main electronic governing box. Refer to "8.2: Main Governor Box".

Mode 3-Emergency Shutdown Pushbutton Inoperative

NOTE: This pushbutton not only trips the intake air shut-off devices, but also opens the current path for the drive signal between the electronic governor and the rack actuator. This troubleshooting investigation must verify the correct functioning of both shutdown modes.

6.6.5.1: Problem With SR2.

Visually monitor the indicator flag on SR2 relay in the remote mounted shutdown box while operating the emergency shutdown pushbutton. The indicator flag should turn from red to green with an operation of the emergency shutdown pushbutton.

If SR2 changes to green go to "6.6.5.2: Problem With The Intake Air Shut-Off".

If SR2 does not change to green, refer to "4.13: Wiring Diagrams" to troubleshoot the remote shutdown box. Measure the voltages at TB396-L1 and TB396-L2 with respect to TB395-R1, first with the emergency shutdown pushbutton released and then with the emergency pushbutton depressed. They should be as follows:

If the readings are normal there is a problem with SR2, replace it.

If all four readings are NOMINAL BATTERY VOLTAGE, temporarily disconnect one of the wires from the emergency shutdown switch to TB396-L1 or TB396-L2. Note the status of the indicator flag on SR2.

If it turns green there is a permanent short circuit between TB396-L1 and TB396-L2 in the locomotive electrical system. Refer to the locomotive prints for detailed troubleshooting.

If it stays red there is a permanent short circuit between TB396-L1 and TB396-L2 in the shutdown box. Refer to "4.13: Wiring Diagrams" for detailed troubleshooting.

6.6.5.2: Problem With The Intake Air Shut-Off

If SR2 changes to green with the emergency shutdown pushbutton depressed and the engine stays running, there is a problem with the intake air shut-offs.

Measure the voltages at the following points in the remote shutdown box with respect to TB395-R1 with the emergency shutdown button depressed. The results should be:

Reference to "4.13: Wiring Diagrams" and a process of elimination should identify where the problem is.

NOTE: If there were a loss of continuity between TB396-L10 to TB252-B1 to the air shut-off solenoid to TB252-B2 to TB395-R5, SR1 would not energize and the engine would not be able to run.

6.6.5.3: Problem With SR1

If the SR2 flag changes to green when the emergency shutdown pushbutton is depressed and the SR1 flag stays red, measure the voltages at the following points in the remote shutdown box with respect to TB395-R1 with the emergency shutdown button depressed. The results should be:

If all the above measurements are OK there is a problem in SR1. Replace SR1.

Reference to "4.13: Wiring Diagrams" and a process of elimination should identify where the problem is if one of the voltages is wrong.

Mode 4-Mechanical Shutdown Lever Inoperative.

If this lever does not work, the only way to shut the engine down is with the emergency shutdown switch which trips the intake air shut-off devices.

6.6.6.1: Problem With The Rack Linkage Or The Actuator Binding

Disconnect the rack linkage from the actuator and check each for binding. Repair damaged parts.

6.7: Engine Governor Indicating A Diagnostic Code

Probable Cause

The Caterpillar Electronic Locomotive Governor System can display up to 14 diagnostic codes. Generally these indicate a problem in the electrical connections to the governor, either in the connections to the engine mounted sensors, or in the connections to the locomotive propulsion system. Each diagnostic code has a fail-safe strategy associated with it ranging from "no action" to "limiting tractive" effort to "shutting the engine down". Refer to "7.2.2: Engine System Defects and 7.2.3: Locomotive System Defects" for details of these fail-safe responses.

Refer to "Section 7: Diagnostic Code Troubleshooting" for detailed troubleshooting of any diagnostic code.

NOTE: For "Stuck Rack Linkage" (code 6), refer to "6.8: Engine Stalls At Low RPM" before referring to "Section 7: Diagnostic Code Troubleshooting".

If "Rack Slew Rate" (code 5) is being displayed while the engine speed is erratic refer to "6.4: Erratic Engine Speed" before referring to "Section 7: Diagnostic Code Troubleshooting".

It is normal for the "Rack Slew Rate" (code 5) to be displayed during start up and shutdown, especially if the engine oil is cool. This display code will normally clear after five seconds. Refer to "Section 7: Diagnostic Code Troubleshooting" only if the display of this code persists, or is displayed with a properly warmed up engine.

6.8: Engine Stalls At Low RPM

Introduction

This symptom may be accompanied by an electronic governor system diagnostic code 6 (Stuck Rack). Refer to "7.2.2: Engine System Defects and 7.2.3: Locomotive System Defects".

It is possible that a fuel starvation condition could cause the electronic governor system to drive the rack actuator so that the rack linkage is against the maximum stop and still not hold idle speed properly. If this were to happen the electronic governor system will display a diagnostic code 6, but it would not be indicative of a problem in the rack linkage.

Probable Cause

Refer to "Problem 9: Engine Stall At Low RPM" in the Troubleshooting section of Systems Operation Testing And Adjusting, 3500 Locomotive Engines, SENR4637.

6.9: Engine Will Not Load

Probable Cause

* Locomotive Controls Set Wrong

* Electronic Governor System Diagnostic Code

* Locomotive Electrical System Problem

* Electronic Governing System

Locomotive Controls Set Wrong

Check all the locomotive controls (isolate switch, generator field switch, etc) for wrong setting and set correctly if necessary. If controls check ok proceed to "6.9.3: Electronic Governor System Diagnostic Code".

Electronic Governor System Diagnostic Code

Check for an electronic governing system diagnostic code. If there is no code being displayed proceed to "6.9.4: Locomotive Electrical System Problem". If there is a code displayed, proceed as follows:

The following electronic governor system diagnostic codes would cause either zero, or very low, excitation current:

* Code 3-Derate Module

* Code 10-Low Motor Current Sense (limit motor current to 100 amps)

* Code 11-High Differential Motor Current

* Code 14-Open Circuit Exciter Path (sets excitation to give approximately 400 generator amps with stalled motors).

In addition to the above responses, when in load test mode, the electronic governor system sets zero excitation current for the following defects:

* Code 8-Generator Current Sense

* Code 9-Generator Voltage Sense

Code 14 would be annunciated as a natural consequence of some of the no load conditions. If code 14 alone, or code 14 and code 6 are being displayed, proceed to "6.9.3.1: Diagnostic Code 14".

If any of the other above defects are being displayed proceed to the "Section 7: Diagnostic Code Troubleshooting".

6.9.3.1: Diagnostic Code 14

6.9.3.1.1: Probable Cause

* No Exciter Power

* Fuel Or Intake Air Starvation Or Mechanically Binding Rack Linkage

* Open Circuit Exciter Current Path

* Loss Of Pacesetter Signal

* High Voltage Sense Signal

* Simultaneous Loss Of Generator Current Sense, High Motor Current Sense And Low Motor Current Sense

6.9.3.1.2: No Exciter Power

1. Check that the exciter power circuit breaker has not tripped. Reset if necessary.

2. Check that battery voltage is on TB391-L4 with respect to TB391-L7 Refer to "4.12: Installation Diagrams (diagram 9). If battery voltage is not on TB391-L4 with respect to TB391-L7 refer to locomotive prints to troubleshoot.

6.9.3.1.3: Fuel Or Intake Air Starvation Or Mechanically Binding Rack Linkage

NOTE: If for any reason the engine requires an excessively high rack position to idle, or cannot carry the load being imposed and starts to lug down in speed, the generator excitation will reduce to avoid the engine being stalled.

The most likely cause is fuel starvation caused by blocked filters, air in fuel line, low fuel pressure, etc.

It is possible that a lug condition could also result from air starvation. This would also be accompanied by excessive steady state smoke in the traction power notches. Refer to 3500 Locomotive Engines, Personality Module Settings, SENR187 for which notches these are.

If a lug condition is evident and is maintained for a sufficient length of time (possibly several minutes) Diagnostic Code 6 would also be displayed.

1. Install and calibrate digital rack sensor (8T1000 Electronic Position Indicator Group). Refer to Special Instruction, SEHS8623 to install correctly.

NOTE: An accessory kit (Probe Contactor Point Group 6V6042) is available that contains a selection of different length extensions for the 8T1000 Electronic Position Indicator Group. The extension is the same for all 3500 engines. The correct extension should be chosen so that the 8T1000 rack sensor will properly display shut-off rack position as well as the maximum mechanical position. All 3500 engines require the sensor to be set up to display increasing rack with a retracting sensor.

2. Remove the calibration pin and start the engine. Note what position the rack goes to with the engine running at idle speed with a no load condition.

This rack position would normally be -4 to -6 mm (-.16 to -.24 in). If it is excessively high (2 mm [.08 in] or more) there is a problem with the fuel system. This is the cause of the no load condition. Check the fuel filters, fuel pressure, air in fuel line, mechanically binding rack linkage etc and replace/repair according to "Problem 9: Engine Stall At Low RPM" in the Troubleshooting section of Systems Operation Testing And Adjusting, SENR4637.

3. Check the idle speed. Compare it with the setting defined in 3500 Locomotive Personality Module Settings, SENR5187 for the personality module fitted to the locomotive.

4. Check the notch 1 speed. Compare it with the setting defined in 3500 Locomotive Personality Module Settings, SENR5187 for the personality module fitted to the locomotive.

5. If the idle or notch 1 speed indicate the engine speed is being lugged down by more than 25 rpm steady state, and there are no abnormal levels of smoke emissions, the engine may be starved of fuel. Check the fuel filters, fuel pressure, air in fuel line, mechanically binding rack linkage etc. Refer to "Problem 9: Engine Stall At Low RPM" in the Troubleshooting section of Systems Operation Testing And Adjusting, SENR4637.

6. If the idle or notch 1 speed indicate the engine speed is being lugged down by more than 25 rpm steady state, and there are abnormal levels of smoke emissions, the intake air filters may be blocked. Check the filters and replace if needed.

6.9.3.1.4: Open Circuit Exciter Current Path

The possible causes of this are:

* High Contact Resistance On Generator Field Contactor

* High Resistance Connection To Exciter Coil

* Open Circuit Exciter Coil

* Defective Wiring In Electronic Governing System Mounting Group

* Defective Main Electronic Governing Box

With reference to "4.12: Installation Diagrams (diagram 9)":

1. De-energize the exciter battery power to TB391-L4 and TB391-L7.

2. Disconnect the exciter coil and generator field contactor connections from either TB391-L4 and TB391-L5, or TB391-L6 and TB391-L7 (reference should be made to the locomotive prints to determine which connection configuration is used).

3. Set the locomotive controls in the state to close the generator field contactor and measure the resistance across the series combination of generator field contactor contact and exciter coil; ie the locomotive system wires that connected to either TB391-L4 and TB391-L5, or TB391-L6 and TB391-L7.

Refer to the generator manufacturer's service manual for the correct exciter coil resistance.

4. If Step 3 indicates the incorrect resistance, refer to the locomotive prints to assist in determining where the problem is (the generator field contactor, the locomotive wiring, or the generator exciter coil).

5. If Step 3 indicates the correct resistance, monitor the initial value of exciter current when switching from idle to notch 1. "Section 4: Installation" includes the recommendation that the locomotive system include a monitor point for the exciter drive current (using a 0.1 ohm series resistance). At the instant the generator field contactor closes, the exciter current should be a minimum of 1-2 amps. It will decay at some rate to zero before code 14 is displayed. If the decay rate is very fast it may be necessary to monitor this with an oscilloscope in order to accurately determine the initial value.

6. If Step 5 value is correct, proceed to "6.9.3.1.5: Loss Of Pacesetter Signal".

7. If Step 5 value is incorrect, the problem is in the electronic governor system. Refer to "4.12: Installation Diagrams (diagram 22) to check the wiring and connectors between J1/4, J1/5, J1/6, J1/7, TB391-L4, TB391-L5, TB391-L6, and TB391-L7. Repair as necessary.

8. If Step 7 shows no defects, replace main electronic governor box according to "8.2: Main Governor Box".

6.9.3.1.5: Loss Of Pacesetter Signal

1. Measure the voltage on TB392-R6 with respect to TB391-L9. This should normally be at a minimum of 50 Volts DC.

2. If Step 1 shows less than zero volts, this may be the cause of the diagnostic code 14. Proceed to "6.24: Low Pacesetter Signal". Correct the pacesetter problem, then check for no loading. If continued no loading, proceed to "6.9.3.1.6: High Voltage Sense Signal".

3. If Step 1 results are more than 50 Volts DC, go to "6.9.3.1.6: High Voltage Sense Signal".

6.9.3.1.6: High Voltage Sense Signal

1. Measure the voltage on TB391-L11 with respect to TB391-L9 when switching from idle to notch 1 with a stalled locomotive. Convert this to the equivalent generator voltage from the scale factor for the particular locomotive. Refer to 3500 Locomotive Personality Module Settings, SENR5187 for the scale factor.

2. Refer to 3500 Locomotive Personality Module Settings, SENR5187 for the programmed generator voltage limit in the personality module. Compare Step 1 results with the programmed limit. If Step 1 results exceed the programmed limit at any time, this is the cause of diagnostic code 14. Proceed to "6.21: Incorrect Scaling Of Generator Voltage Sense".

3. If the programmed generator voltage limit is less than Step 1 results, proceed to "6.9.3.1.7: Simultaneous Loss Of All Current Sense".

6.9.3.1.7: Simultaneous Loss Of All Current Sense

1. Monitor the initial value (immediately after switching from idle to notch 1) of the voltages at the following points with respect to TB391-L9:

* TB391-L10

* TB392-R4

* TB392-R5

At the instant the generator field contactor closes there should be a minimum of 0.6 Volts DC. These signals will decay at some rate to zero before code 14 is displayed. If the decay rate is very fast it may be necessary to monitor them with an oscilloscope in order to accurately determine the initial values.

2. If Step 1 fails and all three current feedback signals fail to exceed 0.6 Volts DC, there is a problem with all three signals. Refer to 6.21: Incorrect Scaling Of Generator Voltage Sense, 6.22: Incorrect Scaling Of Generator Current Sense and 6.23: Incorrect Scaling Of Motor Current Sense".

3. If Step 1 results are OK, an error has been made in following this procedure. Return to "6.9.3.1: Diagnostic Code 14".

Locomotive Electrical System Problem

6.9.4.1: Loss Of Generator Load Signal

The electronic governor system will not load if it does not receive a "generator load" signal on TB391-L1. Refer to "4.12: Installation Diagrams (diagram 9)".

With the locomotive controls set to load in notch 1, note the status of the LED on the front face of the main electronic governor box that is labelled MOTORING/BRAKING/GENERATOR-UNLOAD. This should be on continuously.

If the LED is on continuously proceed to "6.9.4.2: Pacesetter".

If the LED is flashing this indicates the control is receiving a false DYNAMIC BRAKE SELECT signal, proceed to "6.9.4.3: False Dynamic Brake Select Signal".

If the LED is off, measure the voltage on TB391-L1 with respect to TB391-R3. This should be at NOMINAL BATTERY VOLTAGE. If this voltage is not at nominal battery voltage, there is a problem in the locomotive electrical system. Refer to the locomotive prints for detailed trouble-shooting. If this voltage is at NOMINAL BATTERY VOLTAGE, there is a problem in the electronic governor system. Proceed to "6.9.5.1: Loss Of Generator Load Signal".

6.9.4.2: Pacesetter

Measure the pacesetter input signal at TB392-R6 with respect to TB391-L9. Refer to "4.12: Installation Diagrams (diagram 11). If it is greater than 50 Volts DC there is no problem with this function. Proceed to "6.9.5: Electronic Governor System Problem".

If the pacesetter input signal is below 50 volts DC, it could be the cause of the "no loading" condition.

Proceed to "6.24: Low Pacesetter Signal". Correct the pacesetter problem and then check for no loading. If continued no loading proceed to "6.9.4.3: False Dynamic Brake Select Signal".

6.9.4.3: False Dynamic Brake Select Signal

1. Measure the voltage on TB391-L2 with respect to TB391-R3. In normal motoring (or load test mode) or in a locomotive not equipped with dynamic brakes, this should be zero volts.

2. If Step 1 voltage is not zero, disconnect the locomotive electrical system wire to TB391-L2 and measure the voltage on TB391-L2 with respect to TB391-R3. This should be zero volts. If it is not there is a problem in the locomotive electrical system. Refer to the locomotive prints for detailed troubleshooting.

3. If Step 1 or Step 2 voltage is zero, proceed to "6.9.5.2: False Dynamic Brake Selection".

Electronic Governor System Problem

If not directed to "6.9.5.1: Loss Of Generator Load Signal or 6.9.5.2: False Dynamic Brake Selection" from other sections of "6.9: Engine Will Not Load" proceed directly to "6.9.5.3: Incorrect Generator Voltage Sense Scaling".

6.9.5.1: Loss Of Generator Load Signal

Refer to "4.12: Installation Diagrams (diagram 22)". Disconnect the J1 connector to the main electronic governing box and check the continuity between TB391-L1 and J1/1. Repair or replace as necessary.

If OK, check for damage to connector pins and sockets or poorly retained pins or sockets. Repair or replace as necessary.

If connector pins and sockets are OK, replace the main electronic governor box. Refer to "8.2: Main Governor Box".

6.9.5.2: False Dynamic Brake Selection

Refer to "4.12: Installation Diagrams (diagram 22)". Disconnect the J1 connector to the main electronic governing box and check for loss of continuity between TB391-L2 and J1/2. Check for short circuits between J1/2 and any other TB391/TB392 connections or J1 or J2 connector pins. Repair or replace as necessary.

If OK, check for damage to connector pins and sockets or poorly retained pins or sockets. Repair or replace as necessary.

If connector pins and sockets are OK, replace the main electronic governor box. Refer to "8.2: Main Governor Box".

6.9.5.3: Incorrect Generator Voltage Sense Scaling

The electronic governing system includes a generator voltage limiting function. The voltage limit is a function of the notch position. If the voltage feedback scale factor is incorrect and high, a no load condition may result. A low load condition (in the notches in which the traction power control mode is active) would be more probable.

Although there may be some delay after switching from idle to notch 1, if this defect is causing the no load condition, it will eventually (within 30 seconds) produce a diagnostic code 14. For further details refer to "6.9.3.1: Diagnostic Code 14" in particular "6.9.3.1.6: High Voltage Sense Signal". Perform procedures in "6.9.3.1.6: High Voltage Sense Signal" and then if necessary proceed to "6.9.5.4: High Generator Current Sense.

6.9.5.4: High Generator Current Sense Signal

1. Measure the voltage on TB391-L10 with respect to TB391-L9 when switching from idle to notch 1 with a stalled locomotive. Convert this to the equivalent generator current from the scale factor for the particular locomotive. Refer to 3500 Locomotive Engines Personality Module Settings, SENR5187 for the scale factor.

2. Refer to 3500 Locomotive Engines Personality Module Settings, SENR5187 for the programmed generator current limit in the personality module. Compare Step 1 results with the programmed limit. If Step 1 results exceeds the programmed limit at any time, this is the cause of the no load condition. Proceed to "6.22: Incorrect Scaling Of Generator Current Sense".

3. If the programmed generator current limit is less than Step 1 results, proceed to "6.9.5.5: High-High Motor Current Sense-Signal".

6.9.5.5: High-High Motor Current Sense-Signal

1. Measure the voltage on TB392-R4 with respect to TB391-L9 when switching from idle to notch 1 with a stalled locomotive. Convert this to the equivalent motor current from the scale factor for the particular locomotive. Refer to 3500 Locomotive Engines Personality Module Settings, SENR5187 for the scale factor.

2. Refer to 3500 Locomotive Engines Personality Module Settings, SENR5187 for the programmed motor current limit in the personality module. Compare Step 1 results with the programmed limit. If the Step 1 results exceed the programmed limit at any time, this is the cause of the no load condition. Proceed to "6.23: Incorrect Scaling Of Motor Current Sense".

3. If the programmed motor current limit is less than Step 1 results, proceed to "6.9.5.6: High-Low Motor Current Sense-Signal".

6.9.5.6: High-Low Motor Current Sense-Signal

1. Measure the voltage on TB392-R5 with respect to TB391-L9 when switching from idle to notch 1 with a stalled locomotive. Convert this to the equivalent motor current from the scale factor for the particular locomotive. Refer to 3500 Locomotive Engines Personality Module Settings, SENR5187 for the scale factor.

2. Refer to 3500 Locomotive Engines Personality Module Settings, SENR5187 for the programmed motor current limit in the personality module. Compare Step 1 results with the programmed limit. If Step 1 results exceed the programmed limit at any time, this is the cause of the no load condition. Proceed to "6.23: Incorrect Scaling Of Motor Current Sense".

3. If the programmed motor current limit is less than Step 1 results, this is not the cause of the no load condition.

4. If no cause has been identified for the no load condition, an error has been made in following the procedures. Start at the beginning of "6.9: Engine Will Not Load".

6.10: Engine Speeds Correct And Power Incorrect

Probable Cause

* Electronic Governor System Diagnostic Code

* Low Pacesetter Input Signal

* Incorrect Calibration Of Rack Position Sensor

* Power Derate Condition

* High Coolant Temperature

* Linear Derate

* Step Derate

* Low Barometric Pressure

* Incorrect Scaling On Traction Parameter Sense Signal

* Generator Voltage Sense Signal

* Generator Current Sense Signal

* High Motor Current Sense Signal

* Low Motor Current Sense Signal

Electronic Governor System Diagnostic Code

The following electronic governor system diagnostic codes will cause a low, or near-zero excitation current:

Code 1-Rack Position Sensor (revert to an inferred back-up rack position).

Code 9-Generator Voltage Sense(limit motor current to 600 amps).

Code 10-Low Motor Current Sense (limit motor current to 100 amps).

Code 13-High Motor Current Sense (limit motor current to 400 amps).

Code 14: Open circuit exciter current path (drive the exciter open loop at a level that provides approximately 400 generator amps with a stalled locomotive).

In addition to the above responses, when in load test mode, the electronic governor system sets zero excitation current for the following defects (see "6.9: Engine Will Not Load" and "7.2: Diagnostic Code Summary"):

Code 8-Generator Current Sense.

Code 9-Generator Voltage Sense.

If any of the other above defects are being displayed proceed to "Section 7: Diagnostic Code Troubleshooting".

6.10.2.1: Diagnostic Code 1

Diagnostic Code 1 is the "Rack Sensor Failure" diagnostic code. If the electronic governing system diagnoses this defect, the rack position feedback signal used to control engine power is a back-up position that is inferred from the rack actuator drive current.

Prior to the rack sensor failure, the electronic governing system was building up a data base to generate a correlation between measured rack feedback position and the rack actuator drive current.

After the rack sensor failure, the electronic governing system uses this correlation to infer rack position from the rack actuator drive current.

Immediately after the electronic governing system is energized with battery power (on TB391-L8 and TB391-L9) there has been insufficient data gathered to generate an accurate correlation. During this time the data base is preset with values that are conservatively set to produce low engine power. Also during this time the data base is being updated with measured data and the correlation is progressively (with time) becoming more accurate.

Refer to "7.3: Code 1-Rack Sensor" to troubleshoot this diagnostic code.

After rectifying the defect, perform a load test according to "8.27: Load Testing The Engine". Compare the powers in each notch with the nominal powers identified in 3500 Locomotive Engines Personality Module Settings, SENR5187 and confirm they are now correct.

6.10.2.2: Diagnostic Code 9

Refer to "7.10: Code 9-Generator Voltage Sense" to troubleshoot this diagnostic code.

6.10.2.3: Diagnostic Code 10

Refer to "7.11: Code 10-Low Motor Current Sense" to troubleshoot this diagnostic code.

6.10.2.4: Diagnostic Code 13

Refer to "7.13: Code 13-High Motor Current Sense" to troubleshoot this diagnostic code.

6.10.2.5: Diagnostic Code 14

Refer to "7.14: Code 14-Open Circuit Exciter Path" to troubleshoot this diagnostic code.

Low Pacesetter Signal

Measure the pacesetter input signal at TB392-R6 with respect to TB391-L9 (refer to "4.12: Installation Diagrams diagram 11"). If it is greater than 50 Volts DC there is no problem with this function, proceed to "6.10.4: Incorrect Calibration Of Rack Position Sensor".

If the pacesetter input signal is below 50 volts DC, it reduces the motor current maximum limit and could be the cause of the "low power" condition. Refer to "6.24: Low Pacesetter Signal" to troubleshoot.

Incorrect Calibration Of Rack Position Sensor

Check the calibration of the rack position sensor according to "8.15: Rack Sensor".

If re-calibration was necessary, perform a load test according to "8.27: Load Testing The Engine". Compare the powers in each notch with the nominal powers identified in 3500 Locomotive Engines Personality Module Settings, SENR5187 and confirm they are now correct.

Incorrect Scaling Of Generator Current Sense

Check the calibration of the generator current sense according to "8.19: Generator Current Sense Scale Factor".

If incorrect refer to "6.22: Incorrect Scaling Of Generator Current Sense" to troubleshoot.

Incorrect Scaling Of Motor Current Sense

Check the calibration of the motor current sense according to "8.20: Motor Current Sense".

If incorrect refer to "6.23: Incorrect Scaling Of Motor Current Sense" to troubleshoot.

Incorrect Scaling Of Generator Voltage Sense

Check the calibration of the generator voltage sense according to "8.18: Generator Voltage Sense Scale Factor".

If incorrect refer to "6.21: Incorrect Scaling Of Generator Voltage Sense" to troubleshoot.

Power Derate

6.10.8.1: Introduction

The electronic governing system is equipped with two power derate features. It should be noted that perfectly normal environmental conditions could be the cause of the two power derate conditions. The investigator should review the complaint data and the history log of the locomotive to eliminate any possible "natural causes" such as high altitude or tunnel operation.

6.10.8.2: Load Test

Perform a load test according to "8.27: Load Testing The Engine". For each notch position, note the generator voltage sense and generator current sense signals by measuring the voltages on TB391-L10 (current sense) and TB391-L11 (voltage sense) with respect to TB391-L9.

For each notch, note the status of the SHUTDOWN/POWER DERATE/ENGINE RUN status LED on the front face of the main electronic governor box.

For each notch note the rack position. Install and calibrate digital rack sensor (8T1000 Electronic Position Indicator Group). Refer to Special Instruction, SEHS8623 to install correctly.

6.10.8.3: Test For A Power Derate Condition

1. Refer to 3500 Locomotive Engines Personality Module Settings, SENR5187. Note the notches in which gross engine power control mode is active.

2. Refer to the load test results and note the status of the SHUTDOWN/POWER DERATE/ENGINE RUN status LED when the gross engine power control mode was active.

3. If this SHUTDOWN/POWER DERATE/ENGINE RUN status LED was on continuously when the gross engine power control mode was active there is no power derate condition active. Proceed to "6.10.9: Rack Sensor Problem".

4. If this SHUTDOWN/POWER DERATE/ENGINE RUN status LED was flashing when the gross engine power control mode was active there is a power derate condition active. Proceed to "6.10.8.4: Test For Which Power Derate Condition Is Active".

6.10.8.4: Test For Which Power Derate Condition Is Active

1. Run the engine back up to the loaded condition in which the power derate condition was active and confirm it is still active.

The possible causes of a power derate condition being active are as follows:

* Step Temperature Derate Active

* Coolant Temperature Derate Active

* Altitude Derate Active

2. Measure the voltage on TB392-R8 with respect to TB391-L9. This voltage is a function of the coolant temperature exiting the water pump.

3. 3500 Locomotive Engines Personality Module Settings, SENR5187 indicates the equation on relating temperature to voltage plus the coolant temperature above which the derate function becomes active. Use this value in the above formula (in Step 2) to determine the voltage on TB392-R8 below which the derate function becomes active.

4. If the measured voltage from Step 2 is greater than the computed voltage from Step 3, there is no temperature derate condition.

There must be an altitude derate condition. Proceed to "6.10.8.6: Altitude Derate Condition Active".

5. If the measured voltage from Step 2 is less than the computed voltage from Step 3, there is a temperature derate condition. Proceed to "6.10.8.5: Temperature Derate Condition Active".

6.10.8.5: Temperature Derate Condition Active

1. Use 6V9130 Temperature Adapter Group to measure the coolant temperature exiting the water pump. Special Instruction, SEHS8382 provides complete instructions for use of the 6V9130 Temperature Adapter Group.

The oil cooler bonnet has a 1/4 inch pipe plug that can be removed and replaced with a 5P2725 self sealing probe. The 6V9131 hand held probe can be inserted into this self-sealing probe to measure the coolant temperature. At this location the coolant temperature is the same as the location of the temperature derate probe. After taking the measurement, ensure that the plug is replaced on the self-sealing probe.

2. Re-start the engine and run it up to the loaded condition in which the power derate condition was active (and confirm it is still active).

3. Monitor the voltage on TB392-R8 with respect to TB391-L9. Compute the equivalent temperature from this voltage with the equation in Personality Module Settings, SENR5187 that relates temperature to voltage.

Compare the measured temperature (from Step 1) with the computed equivalent temperature (from Step 2).

If the two temperatures correlate within two °C the electronic governing system is working correctly and the horse power is being properly derated. If ambient conditions are such that the engine should be at full power, refer to "Problem 28: Engine Coolant Is Too Hot" in the Troubleshooting section of 3500 Locomotive Engines, Systems Operation Testing And Adjusting, SENR4637.

4. If the two Step 3 temperatures do not correlate, monitor the voltage at the derate module terminal 4 with respect to terminal 6 and compare it with the voltage at TB392-R8 with respect to TB391-L9.

If these two voltages are not the same, there is a problem in the wiring of the electronic governing system mounting group. Proceed to "6.10.10: Harness Error On Electronic Governor Mounting Group".

5. If the two Step 3 voltages are the same, monitor the voltage change on TB251-T4 with respect to TB251-T6 as the locomotive system wire to TB392-R8 is disconnected.

If this voltage reading increases, there is a problem with the Electronic Governor having too low an input impedance. Replace the wire on TB392-R8 and proceed to "6.10.11: Attenuated Temperature Derate Signal".

6. If the voltage reading in Step 5 stays the same and is greater than zero, go to Step 10.

If the voltage reading in Step 5 is equal to zero, the Step Derate switch may be active. Go to Step 7.

7. To check the Step Derate Switch remove the lid to the electrical harness pull-thru box mounted on the right hand side of the engine front housing to the rear of the rack actuator. Disconnect the sensor wires to the terminal block inside the box (TB254-T3 & TB254-T4 respectively). Measure the voltage on TB251-T4 with respect to TB251-T6.

If it is still 0 volts go to Step 10.

8. If Step 7 voltage is now more than 0 volts, the step derate function was active. Note the water jacket temperature on the instrument panel.

If it is less than 104 ± 2.8°C, replace the step derate switch according to "8.10: Step (Temperature) Derate Switch".

9. If step 8 temperature is more than 104 ± 2.8°C, the step derate function is active and the engine is being properly derated. If ambient conditions are such that the engine should be at full power, refer to "Problem 28: Engine Coolant Is Too Hot" in the Troubleshooting section of 3500 Locomotive Engines, Systems Operation Testing And Adjusting, SENR4637.

10. Remove the lid to the electrical harness pull-thru box mounted on the right hand side of the engine front housing to the rear of the rack actuator. Disconnect the sensor leads to the terminal block inside the box (TB254-B1 & TB254-B2 respectively). Measure the resistance between the sensor leads.

Compare the temperature and the corresponding sensor resistance with the values shown in the Thermistor Table. This table contains the correlation between the temperature and sensor resistance.

If the resistance and temperature measurements do not correlate, replace the sensor according to "8.7: Water Temperature Sensor".

If the resistance and temperature measurements correlate, re-connect the sensor leads to TB254 and proceed to Step 11.

11. Disconnect the engine harness leads from the temperature interface module terminals 1 & 2 (located in the junction box on the right hand side of the rear flywheel housing).

Repeat the temperature and resistance measurements of Step 10 except now measure the resistance between the engine harness leads.

If the resistance and temperature measurements correlate re-connect the harness leads and proceed to Step 12.

If the resistance and temperature measurements do not correlate, there is a problem in the engine harness between the main junction box containing the temperature interface module and the small pull-thru box containing TB254. Refer to the "4.13: Wiring Diagrams" to troubleshoot.

12. Check the temperature interface module according to "8.17: Temperature Interface Module".

If the temperature interface module is not OK, replace the temperature interface module according to "8.8: Temperature Interface Module".

If the temperature interface module checks out OK an error has been made in following this procedure. Go back to Step 1 and repeat procedure.

6.10.8.6: Altitude Derate Condition Active

1. Remove the hose to the O-ring port on the side of the derate module. Note whether the SHUTDOWN/POWER DERATE/ENGINE RUN status LED on the main electronic governor box stays flashing.

2. If the SHUTDOWN/POWER DERATE/ENGINE RUN status LED on the main electronic governor box stays flashing, note the barometric pressure. Refer to 3500 Locomotive Engines Personality Module Settings, SENR5187 to determine the ambient pressure below which the altitude derate function starts. If the ambient pressure is greater than this pressure, there is a problem with the DERATE module which is mounted on the electronic governing system's mounting group. Replace the DERATE module according to "8.4: Altitude Derate Module".

3. If the SHUTDOWN/POWER DERATE/ENGINE RUN status LED on the main electronic governor box stops flashing, it indicates that the absolute pressure in the hose to the derate module is less than the ambient pressure below which the altitude derate function starts.

The hose should be connected to the intake air passage of the engine downstream of the air cleaners and upstream of the turbo charger air intake. This symptom could indicate an excessive air intake restriction in the air cleaners. Refer to the Air Intake And Exhaust System section of 3500 Locomotive Engines, Systems Operation Testing And Adjusting, SENR4367 to check out the air cleaner restriction.

4. Connect the O-ring port on the side of the derate module to a regulated vacuum source and monitor the pressure to the port with an absolute pressure gauge. Load the engine in the lowest notch in which the gross engine power control mode is active (refer to 3500 Locomotive Engines Personality Module Settings, SENR5187). Slowly reduce the pressure to the port and note the port pressure when the SHUTDOWN/POWER DERATE/ENGINE RUN status LED on the main electronic governor box starts to flash. Compare this pressure with the value indicated in SENR5187.

If the two pressures are within 2 kPa, there is no problem with the derate module.

5. If the two pressures differ by more than 2 kPa there is a problem with DERATE module. Replace it according to "8.4: Altitude Derate Module".

Rack Sensor Problem

1. Review the results of "6.10.8.2: Load Test". Compare the rack positions and power levels with the nominal values identified in 3500 Locomotive Engines Personality Module Settings, SENR5187.

2. If the rack positions are correct within ± .24 mm (.009 in) there is no problem with the electrical system. The electrical system is performing the task of running the engine at the prescribed speed and rack positions. If the power levels are wrong, it is because there is either an engine problem (low boost, incorrect timing, wrong fuel, defective injector, wrong injector calibration). Refer to the Troubleshooting section in 3500 Locomotive Engines, Systems Operation Testing And Adjusting, SENR4637. There could also be a parasitic load problem. Check the parasitic loads in each notch.

3. If some, or all, of the rack positions are incorrect (outside a band of ± .24 mm [.009 in]) the problem must be a non linear rack position sensor.

Replace and calibrate the rack position sensor according to "8.9: Rack Position Sensor and 8.15: Rack Position Sensor".

Repeat "6.10.8.2: Load Test" and confirm the rack positions and powers are now correct.

Harness Error On Electronic Governor Mounting Group

Turn off all power to the mounting group of the electronic governor.

Check the continuity between TB392-R8 and the derate module terminal 4.

If this is OK an error has been made. Return to "6.10.8.5: Temperature Derate Condition Active".

If not OK, make the necessary repairs.

Attenuated Temperature Derate Signal

Turn off all power to the mounting group of the electronic governor.

Check the impedance between TB392-R8 and TB391-L9 with the locomotive system wires disconnected from these two terminals.

This should be 64 K Ohms ± 10 percent. If it is an error has been made. Return to "6.10.8.5: Temperature Derate Condition Active".

If it is not 64 K Ohms ± 10 percent a problem has been confirmed on mounting group.

Disconnect the wire to Terminals 6 and 8 on the derate module mounted on the mounting group.

Check the impedance between Terminals 4 and 6 on the derate module mounted on the mounting group.

This should be 64 K Ohms ± 10 percent. If it is, there is a defect on the wiring on the mounting group of the electronic governor. Refer to "4.12: Installation Diagrams (diagram 22)" to troubleshoot and repair.

If it is not 64 K Ohms ± 10 percent there is a defect with the derate module. Replace according to "8.4: Altitude Derate Module".

If No Cause Is Found

If no cause for the complaint can be found, put the locomotive back in service. Note the complaint in the history log for future review. It is possible that an intermittent problem caused the complaint. Any future complaints should be accompanied by more detailed information:

* Ambient Temperature

* Notch

* Ground Speed

* Traction Motor Current Prior To Fault

* Traction Motor Current During The Fault

* Altitude

* Status Of Electronic Control System LED Display

6.11: Too Much Black Or Gray Smoke

Probable Cause

* Excessive Intake Air Restriction

* Incorrect Fuel Injection Timing

* Tripped Intake Air Shutoff Device

* One Or More Defective Fuel Injectors

Excessive Air Intake Restriction

Refer to Air Intake And Exhaust System in the Testing And Adjusting Section of the Systems Operation Testing And Adjusting for 3500 Locomotive Engines, SENR4367 to check for maximum allowable intake air restriction.

Measure restriction and replace filters if necessary.

Incorrect Fuel Injection Timing

Refer to Fuel Timing in the Testing And Adjusting Section of the Systems Operation Testing And Adjusting for 3500 Locomotive Engines, SENR4367 to check for correct setting of fuel injection timing.

Check fuel timing and reset if necessary.

Tripped Intake Air Shutoff

This is only possible on the 3516 engines which have two shutoffs. Visually inspect both intake air shutoffs to determine whether one has tripped.

Reset if necessary.

One Or More Defective Fuel Injectors

Refer to Fuel Injector Testing in the Testing And Adjusting Section of the Systems Operation Testing And Adjusting for 3500 Locomotive Engines, SENR4367 to check for defective fuel injectors.

Replace any defective injectors.

6.12: Engine Coolant Too Hot

Introduction

The maximum value for the range of normal coolant temperature exiting the engine and entering the radiators (top tank temperature) is defined as 98.9°C (210°F). The cooling system of the locomotive should be adequate to limit the "top tank" temperature to 98.9°C (210°F) with the engine carrying full load in ambient temperatures up to 43.3°C (110°F).

Under abnormal conditions (tunnel operation) where the ambient temperature can be in excess of 43.3°C (110°F), the electronic governing system will reduce the power of the engine by as much as 25 percent (approximately) of rated power.

If the top tank temperature exceeds 104°C (219.2°F) the engine system will trip an alarm signal.

Probable Cause

* Insufficient Coolant

* Defective Pressure Relief Valve

* Defective Water Temperature Regulators

* Defective Cooling Fans

* Incorrect Temperature Settings For Cooling Fans

* Restricted Coolant Flow

* Defective Water Pump

* Too Much Load

* Incorrect Fuel Injection Timing

* Combustion Gases In Coolant

Insufficient Coolant

The engine system is equipped with a low coolant level switch. Normally the engine will shutdown before a coolant leak depletes the coolant system to a sufficient degree to cause an overheating problem.

Check the coolant level. If coolant level is OK proceed to "6.12.4: Defective Pressure Relief Valve". If coolant level is low check for leaks. Repair and replenish coolant.

Also check the "low coolant level" switch. This is not part of the engine package. It is mounted in the cooling system, remote from the engine. The correct location for this switch is determined by the locomotive builder and verified at the time of the commissioning audit for the locomotive. Refer to the locomotive builder's service literature.

Defective Pressure Relief Valve

Check the pressure relief valve. If the pressure relief valve checks OK proceed to "6.12.5: Defective Water Temperature Regulators". If the pressure relief valve does not check OK, replace it.

Defective Water Temperature Regulators

Refer to Testing The Cooling System in the Testing And Adjusting section of Systems Operation Testing And Adjusting, 3500 Locomotive Engines, SENR4637 for the correct procedure to check the water temperature regulators. If OK proceed to "6.12.6: Incorrect Temperature Settings For Cooling Fans". If the water temperature regulators are defective, replace them.

Incorrect Temperature Settings For Cooling Fans

3500 powered locomotives have electrically driven cooling fans that are controlled as a function of the coolant temperature exiting the engine and entering the radiators (top tank temperature). The locomotives may have one, two or possibly three fans. These fans are controlled by temperature switches located in the coolant lines between the engine and the radiators. There may be different setting configurations for different multi-fan installations. All fans should be on with a coolant temperature (top tank temperature) greater than or equal to 92.2°C (198°F).

Check cooling fan control logic for correct operation. If incorrect, refer to appropriate locomotive service literature to remedy.

Incorrect Rotation Of Cooling Fans

During commissioning it is possible for incorrect wiring to the fan motors to cause the fan motors to rotate in the wrong direction. Check for correct rotation and correct any wiring error.

Radiator Shutters Incorrectly Closed

If the locomotive is equipped with radiator shutters, check for correct operation.

Restricted Coolant Flow

Check the cooling system for restrictions. If any are found, remove them.

Defective Water Pump

Check the water pump for low flow rate. If pump is defective make repairs or replace as necessary.

Too Much Load

Refer to "6.10: Engines Speed Correct And Power Incorrect and 8.21: Electronic Speed (Overspeed) Switch" to determine if the load is excessive.

Incorrect Fuel Injection Timing

Refer to "Problem 28: Engine Coolant Is Too Hot" in the Troubleshooting section of the Systems Operation Testing And Adjusting, 3500 Locomotive Engines, SENR4637.

Combustion Gases In Coolant

Refer to "Problem 28: Engine Coolant Is Too Hot" in the Troubleshooting section of the Systems Operation Testing And Adjusting, 3500 Locomotive Engines, SENR4637.

Slow Fan Speed

It is possible to have a problem with the power (220 Volt three phase) to the cause the fan motors to turn too slowly.

Check for and correct any wiring error.

Inadequate Cooling System Design

During commissioning it is possible to experience a cooling problem due to an inadequate cooling system design. This should be identified during the cooling audit that is part of the commissioning procedure.

6.13: Engine Speeds And Power Settings Incorrect

Probable Cause

* Incorrect Personality Module

Incorrect Personality Module

The Caterpillar Electronic Locomotive Governor employs an isochronous engine speed governor. The speeds in each notch are essentially independent of load. Unless the engine speed is randomly wandering (in which case the problem is in the fuel system), the incorrect personality module has been fitted.

Check the part number on the personality module and replace the module with the correct personality module. Refer to "8.3: Personality Module" for the proper replacement procedure.

6.14: Dynamic Brakes Inactive

Probable Cause

* Locomotive Electrical System Problem

* Defective Wiring In Electronic Governor Mounting Group

* Defective Main Electronic Governor Box

Locomotive Electrical System Problem

The Caterpillar Electronic Locomotive Governor is switched to dynamic brake mode under the following conditions:

TB391-L1 is tied to Battery Plus

TB391-L2 is tied to Battery Plus

1. Note the status of the status LED's on the main electronic governor box. In dynamic brake mode the Motoring/Dynamic Brake/Unload LED (second LED from the top) should be flashing.

2. If the Motoring/Dynamic Brake/Unload LED is flashing, the electronic governing system is going into dynamic brake mode. The problem is incorrect grid or field current regulation. Refer to "6.19: Incorrect Regulation Levels In Dynamic Brake Mode".

3. If the Motoring/Dynamic Brake/Unload LED is not flashing, check the voltage on both the above connections with respect to Trainline Battery Negative (TB391-R3).

4. If one or both voltages are not at Battery Plus, refer to the locomotive prints to troubleshoot the locomotive electrical system.

5. If both voltages are at Battery Plus, the problem is in the Electronic Governing System. Proceed to "6.14.3: Defective Wiring On Electronic Governor Mounting Group".

Defective Wiring On Electronic Governor Mounting Group

1. Turn off the battery power to TB391-L8 and TB391-L9.

2. Turn off the battery power to TB391-R2 and TB391-R3.

3. Disconnect the J1 connector from the main electronic governor box.

4. Check the continuity between TB391-L1 and J1/1 and between TB391-L2 and J1/2. Repair any defects.

5. Inspect the J1 harness connector for any damage on pins 1 and 2. Especially look for any pin contacts "pushed in" to the body of the connector. Replace the J1 harness if necessary.

6. If no problems are found, replace the main electronic governor box according to "8.2: Main Governor Box".

6.15: Automatic Sanding Inactive

Probable Cause

* Locomotive Electrical System

* Caterpillar Sanding Relay Or PIR (PEEC Interface Relay)

* Defective Wiring On Electronic Governing Mounting Group

* Defective Main Electronic Governing Box

Locomotive Electrical System

1. Refer to locomotive prints to determine suitable points to check (monitor with a voltmeter) that the PIR is energizing correctly.

2. Hook up voltmeter to these points and perform the procedure outlined in "8.28: Checking Automatic Sanders". Note the voltmeter readings.

3. If Step 2 indicated that the PIR is energizing correctly there is a problem in the locomotive electrical system, refer to the locomotive prints to troubleshoot.

4. If Step 2 indicated that the PIR is not energizing correctly hook up a voltmeter to monitor the DC voltage on TB392-L9 with respect to TB391-L9. Perform the procedure outlined in "8.4: Altitude Derate Module".

5. It should read 12 ± 2 Volts DC while the toggle switch is open.

6. If Step 5 is not 12 ± 2 Volts DC there is a problem in the electronic governing system. Proceed to "6.15.3: Electronic Governing System".

7. If Step 5 is 12 ± 2 Volts DC the problem is outside the electronic governing system. The problem is in the PIR relay itself, or in the locomotive electrical system wiring between TB392-L9 and TB391-L9 and the PIR relay coil.

Refer to the locomotive prints to troubleshoot the problem.

Electronic Governing System

1. Disconnect all battery power to TB391-L4 and TB391-L7, TB391-L8 and TB391-L9, and to TB391-R2 and TB391-R3.

2. Unplug the J1 and J2 connectors to the main electronic governing box.

3. Check the continuity between TB391-L9 and J1/9 and between TB392-L9 and J2/9. Repair any defects.

4. Inspect the J1 harness connector for any damage on pins 1 and 2. Especially look for any pin contacts "pushed in" to the body of the connector. Replace the J1 or J2 harness if necessary.

5. If no problems are found, replace the main electronic governor box according to "8.2: Main Governor Box".

6.16: Engine Spontaneously Shuts Down

Probable Cause

* Electronic Governor System Diagnostic Code

* Emergency Shutdown Condition

* Defect in Safety Shutdown Logic

* Defect in Locomotive Electrical System

* Defect in Engine Harness

* Defect in Electronic Governing System

Electronic Governor System Fault

Check the Diagnostic LED's on the main governor box for a diagnostic code.

Only the following diagnostic codes will initiate a shutdown:

* Code 2-Speed Sensor Fault

* Code 4-Personality Module Fault

Codes 5 and 6 can sometimes be displayed following an emergency shutdown (especially if the shutdown occurred under load). Ignore codes 5 and 6 if they are being displayed.

Proceed to "6.16.3: Emergency Shutdown Condition" if codes 2 and 4 are not being displayed.

If code 2 is being displayed refer to "7.4: Code 2-Speed Sensor".

If code 4 is being displayed refer to "7.6: Code 4-Personality Module".

If any other codes are being displayed, note which codes they are and then proceed to "6.16.3: Emergency Shutdown Condition". After completing "6.16: Engine Spontaneously Shuts Down" proceed to the pertinent sections of "Section 7: Diagnostic Code Troubleshooting" to troubleshoot these other diagnostic codes.

Emergency Shutdown Condition

Check the shutdown annunciator panel for shutdown conditions. Depending on the type of engine and optional package, the following channels can initiate a shutdown:

* Overspeed

* Low Coolant Level

* High Crankcase Pressure (if equipped)

* Low Oil Pressure

If the four conditions are not being displayed, proceed to "6.16.4: Fault In Shutdown Logic".

6.16.3.1: Overspeed Shutdown

If overspeed shutdown annunciation is on, first reset the tripped air intake shutoffs then remove the overspeed switch. Refer to "8.21: Electronic Speed (Overspeed) Switch" to check the switch.

If the overspeed switch is defective, calibrate a new switch and then replace the old switch with the new one. Refer to "8.16: Electronic Speed (Overspeed) Switch and 8.14: Electronic Speed (Overspeed) Switch".

If the overspeed switch is not defective, re-install it. Man the manual rack shut-off lever and attempt to start the engine.

If the engine starts and continues to accelerate in an uncontrolled fashion, operate the manual rack shut-off lever to shut it down. Then proceed to "6.3: Engine Overspeeds" to complete the troubleshooting investigation.

If the engine starts and idles normally, the problem was intermittent. Since the problem is no longer active it is not possible to methodically troubleshoot it. Refer to the fault history log of the locomotive to determine whether a trend has been established of the following fault symptoms:

* Diagnostic code 5 on the electronic governor system

* Erratic engine speed governing

* Overspeed emergency shutdown

All three symptoms can be caused by defects in the following areas which essentially can cause erratic speed governing that could result in an overspeed shutdown:

* Rack actuator

* Wiring between electronic governor and rack actuator

* Rack linkage

* Electronic governor speed sensor

* Wiring between electronic governor and electronic governor speed sensor

Refer to "6.4: Erratic Engine Speed" for detailed troubleshooting.

In addition, a spurious overspeed shutdown can be caused by defects in the following areas:

* Overspeed switch speed sensor

* Wiring between overspeed switch and overspeed switch speed sensor

* Intermittent defect in overspeed switch

* Defect in overspeed switch that causes the overspeed trip point to drift badly with ambient temperature of switch

6.16.3.2: Low Coolant Level

If low coolant level shutdown annunciation is on, check the coolant level. If it is low, refer to Testing And Adjusting in Systems Operation Testing And Adjusting, 3500 Locomotive Engines, SENR4637 to find and repair the leak.

If the coolant level is OK, the low coolant level switch is defective. Replace the coolant level switch.

NOTE: A problem with the engine or locomotive wiring to the low coolant level switch would cause either a false shutdown without any annunciation, or it would cause a false low coolant level annunciation without any shutdown. There would have to be two simultaneous harness defects to both shut the engine down and also to give a low coolant level annunciation.

6.16.3.3: High Crankcase Pressure

If the high crankcase pressure annunciation is on, restart the engine and monitor the crankcase pressure. Typical operating crankcase pressure readings are 0.25 to 0.37 kPa (1.0 to 1.5 in H²O).

If the crankcase pressure is high, refer to Testing And Adjusting section in Systems Operation Testing And Adjusting, 3500 Locomotive Engines, SENR4637.

If the crankcase pressure is normal, check the crankcase pressure contactor. Refer to Specifications, 3500 Locomotive Engines, SENR4636. If the contactor is OK, the engine suffered a temporary high crankcase pressure. If the crankcase pressure contactor is defective, replace it.

NOTE: A problem with the engine or locomotive wiring to the high crankcase pressure contactor would cause either a false shutdown without any annunciation, or it would cause a false high crankcase pressure annunciation without any shutdown. There would have to be two simultaneous harness defects to both shut the engine down and also to give a high crankcase pressure annunciation.

6.16.3.4: Low Oil Pressure

If the low oil pressure annunciation is on, check the two low oil pressure contactors. Refer to 3500 Locomotive Engines Specifications, SENR4636 for the correct contactor settings. Then check the oil step speed switch setting (in the overspeed switch) according to procedures in "8.21: Electronic Speed (Overspeed) Switch".

If the contactor settings are wrong replace the contactors.

If the oil step speed setting is wrong, calibrate a new switch and then replace the old switch with the new one. Refer to "8.16: Electronic Speed (Overspeed) Switch and 8.14: Electronic Speed (Overspeed) Switch".

If both the contactors and the overspeed switch settings are correct there is a low oil pressure problem. Refer to 3500 Locomotive Engines, System Operations Testing And Adjusting, SENR4637 to investigate this problem.

NOTE: A problem with the engine or locomotive wiring to the low oil pressure contactors would cause either a false shutdown without any annunciation, or it would cause a false low oil pressure annunciation without any shutdown. There would have to be two simultaneous harness faults to both shut the engine down and also to give a low oil pressure annunciation.

Fault In Shutdown Logic

There are two methods of shutting the engine down:

* Shutting off the fuel

* Shutting off the intake combustion air

First check the air intake shutoff devices to determine whether they have tripped (3508 and 3512 engines have one electrically actuated shutoff device, 3516 engines have two electro-hydraulically actuated shutoff devices).

If one or more of the air intake shutoff devices have tripped, proceed to "6.16.4.2: Air Intake Shutoff".

If the intake air shutoff devices have not tripped, the engine was shutdown by shutting off the fuel. Proceed to "6.16.4.1: Fuel Shutoff".

6.16.4.1: Fuel Shutoff

Attempt to start the engine. If it does not start proceed to "6.2: Engine Cranks But Will Not Start" to complete the troubleshooting.

If the engine does start, the problem was intermittent and there is no good way to methodically investigate it. Reference must be made to "4.13: Wiring Diagrams".

The problem is likely to be caused by a defect in one of two current paths. This problem could be caused by:

* A broken wire

* A loose connection

* A defective set of relay contacts

The first current path is for energizing relay SR1. This involves:

* The locomotive wiring

* The remote mounted safety junction box

The second current path is for driving the rack actuator from the main electronic governing box. This involves:

* The locomotive wiring

* The remote mounted safety junction box

* The engine wiring

Air Intake Shutoff

If one or more of the air intake shutoff devices has been tripped, (and there is no overspeed annunciation either on the main locomotive annunciator, or on the overspeed switch itself) there is a problem in the overspeed switch or the overspeed switch speed sensor, or the harness between the overspeed switch and its speed sensor.

If this problem is intermittent, the engine should start normally. In this case there is no good way of methodically troubleshooting the problem. It is caused by the crank terminate contacts dropping out while the engine is running. Detailed reference must be made to "4.13: Wiring Diagrams".

If this problem is not intermittent, but permanent, the starters will not automatically drop out during a start when the engine reaches starter cutout speed. The starters will stay energized as long as the start button is activated. The engine will shutdown immediately when the starter button is released.

Attempt to start the engine to determine whether the problem is permanent or intermittent.

If permanent, check the output of the speed sensor with a DVM (set on AC Volts, with a full scale of 20 volts) connected between TB252-T6 and TB252-T7; TB397-L6 and TB397-L7: and between ESS-3 and ESS-4 in the junction box. With the engine cranking, this should read at least 3 volts RMS at each of the three sets of monitoring points.

If the sensor voltage is not OK, replace the overspeed switch speed sensor. Refer to "8.11: Speed Sensor". Repeat the test. If the sensor voltage is now OK, the sensor was defective. If the sensor voltage is still incorrect, the problem is in the sensor wiring between the sensor and the overspeed switch. Refer to "4.13: Wiring Diagrams".

If the sensor voltage is OK, replace the overspeed switch according to "8.16: Electronic Speed (Overspeed) Switch and 8.14: Electronic Speed (Overspeed) Switch".

6.17: Low Motor Or Generator Currents

Probable Cause

* Electronic Governor Set In Self Load

* Electronic Governor Diagnostic Code

* Low Pacesetter Signal

* Incorrect Generator Voltage Sense Scaling

* Incorrect Generator Current Sense Scaling

* Incorrect Motor Current Sense Scaling

* Low Engine Power

Electronic Governor Set In Self Load Mode

Check the status of the LED's on the front face of the main electronic governor box. If the self load LED (fourth from the bottom) is off, proceed to "6.17.3: Electronic Governor Diagnostic Code".

If the self load LED is on, the generator current is limited to a low value. Refer to 3500 Locomotive Engines, Personality Module Settings, SENR5187 for the value for the personality module fitted to the locomotive.

Measure the DC voltage on TB391-L12 with respect to TB391-R3. Battery voltage is "normal" and zero volts is "self load". If the voltage is zero, there is probably a broken or loose connection in the locomotive electrical system. Locate and repair it.

If after the above repairs the self load LED is still on, check the continuity of the mounting group connections between TB391-L12 and J1/12.

Repair any defects that are found.

If the self load LED is still on replace the main electronic governor box. Refer to "8.2: Main Governor Box".

Electronic Governor Diagnostic Code

Check diagnostic LED's on main governor box for a diagnostic code. If there are any faults being displayed, note which ones they are. The response programmed into the electronic governor system for the following codes will allow the generator to load, but will result in a low current symptom:

* Code 9-Generator voltage sense fault

* Code 10-Low motor current sense fault

* Code 13-High motor current sense fault

* Code 14-Open circuit exciter current path

NOTE: If Code 1-Rack Sensor Fault is being displayed this could result in a low power condition which may be interpreted as a low current symptom.

If any of the above codes are being displayed refer to "Section 7: Diagnostic Code Troubleshooting". If any codes other than the ones above are being displayed, they should be investigated by referring "Section 7: Diagnostic Code Troubleshooting" after completing the remainder of "6.17: Low Motor Or Generator Currents".

Low Pacesetter Signal

Refer to "6.24: Low Pacesetter Signal" to check for a low pacesetter signal.

Incorrect Generator Voltage Sense Scaling

Refer to "8.18: Generator Voltage Sense Scale Factor" for the procedure to checkout the voltage sense scaling.

If OK proceed to "6.17.6:Incorrect Generator Current Sense Scaling".

If not OK, refer to "6.21: Incorrect Scaling Of Generator Voltage Sense" for the procedure to troubleshoot incorrect voltage sense scaling.

Incorrect Generator Current Sense Scaling

Refer to "8.19: Generator Current Sense Scale Factor" for the procedure to checkout the generator current sense scaling.

If OK proceed to "6.17.7: Incorrect Motor Current Scaling".

If not OK, refer to "6.22: Incorrect Scaling Of Generator Current Sense" for the procedure to troubleshoot incorrect generator current sense scaling.

Incorrect Motor Current Scaling

Refer to "8.20.2: Total System Check" for the procedure to checkout the motor current sense scaling.

If OK proceed to "6.17.8: Low Engine Power".

If not OK, refer to "6.23: Incorrect Scaling Of Motor Current Sense" for the procedure to troubleshoot incorrect motor current sense scaling.

Low Engine Power

Refer to "6.10: Engine Speeds Correct And Power Incorrect" for the procedure to troubleshoot low engine power.

6.18: Excessive Wheelslip

Probable Cause

* Electronic Governor System Fault

* Incorrect Generator Voltage Sense Scaling

* Incorrect Generator Current Sense Scaling

* Incorrect High Motor Current Sense Scaling

* Inactive Automatic Sanders

Introduction

It should be determined whether this reported fault is an instance of real or indicated wheelslip.

With reference to "4.12: Installation Diagrams (diagrams 11 through 15)", the electronic governor employs a multiplexed output for the following functions:

* Driving the locomotive sanders

* Driving the trainline wheelslip signal

The locomotive electrical system uses a time delay relay to discriminate between these two conditions. This discrimination circuit should first be checked out for correct operation. If it is functioning correctly proceed to "6.18.3: Electronic Governor Diagnostic Code". If not make the necessary repairs and review the failure report in detail to determine whether this failure would explain the symptoms or whether there was genuine excessive wheelslip observed. If genuine excessive wheelslip was observed proceed to "6.18.3: Electronic Governor Diagnostic Code".

Electronic Governor Diagnostic Code

Check Diagnostic LED's on main governor box for a diagnostic code. If there are any codes being displayed, note which ones they are.

The following codes will be accompanied by an excessive wheelslip indication on the trainline:

* Code 10-Low Motor Current Sense Fault

* Code 11-High Differential Current Sense

If any of the above codes are being displayed refer to the appropriate section of "Section 7: Diagnostic Code Troubleshooting" to troubleshoot the problem.

If any codes other than the ones above are being displayed, they should be investigated by referring to "Section 7: Diagnostic Code Troubleshooting" after completing the remainder of "6.18: Excessive Wheelslip".

Incorrect Generator Voltage Sense Scaling

Refer to "8.18: Generator Voltage Sense Scale Factor" for the procedure to checkout the voltage sense scaling.

If OK proceed to "6.18.5: Incorrect Generator Current Sense Scaling".

If not OK, refer to "6.21 Incorrect Scaling Of Generator Voltage Sense" for the procedure to troubleshoot incorrect voltage sense scaling.

Incorrect Generator Current Sense Scaling

Refer to "8.19: Generator Current Sense Scale Factor" for the procedure to checkout the generator current sense scaling.

If OK proceed to "6.18.6: Incorrect Motor Current Scaling".

If not OK, refer to "6.22: Incorrect Scaling Of Generator Current Sense" for the procedure to troubleshoot incorrect generator current sense scaling.

Incorrect Motor Current Scaling

Refer to "8.20.2: Total System Checkout" for the procedure to checkout the motor current sense scaling.

If OK proceed to "6.18.7: Inactive Automatic Sanders".

If not OK, refer to "6.23: Incorrect Scaling Of Motor Current Sense" for the procedure to troubleshoot incorrect motor current sense scaling.

Inactive Automatic Sanders

It is unlikely that inactive automatic sanders will cause excessive wheelslip that could be noticed visually by observing the wheels.

If track conditions are bad, inactive automatic sanders will cause more active wheelslip regulation on the part of the electronic governor which would result in a lower motor current and be perceived as reduced tractive effort.

Also, if track conditions are bad inactive automatic sanders can be perceived as excessive wheelslip by the operator since the status LED on the electronic governor will be on more and there is a higher probability of triggering a trainline wheelslip signal.

Refer to "8.28: Checking Automatic Sanders" for the detailed procedure for checking automatic sanders.

If inoperative, refer to "6.15: Automatic Sanding Inactive" for procedure to troubleshoot automatic sanders.

6.19: Incorrect Dynamic Brake Regulation Levels

Probable Cause

* Truck-Slide Relay Incorrectly Energized Or Defective

* Incorrect 24T Train Line Signal Scaling

* Electronic Governor System Fault

* Incorrect Generator Voltage Sense Scaling

* Incorrect Generator Current Sense Scaling

* Incorrect Motor Current Sense Scaling

Truck-Slide Relay Incorrectly Energized Or Defective

With reference to "4.12: Installation Diagrams (diagrams 11 thru 15 and 21)", the electronic governing system is equipped with an input that allows interface with a truck-slide relay. This relay is used only in dynamic brake mode. The 24T trainline signal scaling into the electronic governing system is grossly attenuated when the relay is energized.

If this relay is incorrectly energized or is defective, it will cause low grid and field current levels.

Not all locomotives are equipped with this relay. If the locomotive being investigated is equipped with this relay, refer to the locomotive prints to troubleshoot it and make any necessary repairs.

Incorrect 24T Trainline Signal Scaling

Refer to "8.22: 24T Signal Scaling" for the procedure to check out the 24T trainline scaling.

If OK proceed to "6.19.4: Electronic Governor System Fault".

If not OK proceed to "6.25: Incorrect 24T Signal Scaling" for the procedure to troubleshoot incorrect 24T trainline signal scaling.

Electronic Governor System Fault

Check diagnostic LED's on main governor box for a diagnostic code. If there are any codes being displayed, note which ones they are.

The response programmed into the electronic governor system for the following codes will result in a low current symptom in dynamic brake mode:

* Code 3-Derate Module

* Code 8-Generator Current Sense

* Code 10-Low Motor Current Sense

* Code 11-High Differential Motor Current Sense

* Code 13-High Motor Current Sense

* Code 14-Open Circuit Exciter Current Path

If any of the above codes are being displayed refer to "Section 7: Diagnostic Code Troubleshooting" to troubleshoot the problem.

Incorrect Generator Voltage Sense Scaling

Refer to "8.18: Generator Voltage Sense Scale Factor" for the procedure to checkout the voltage sense scaling.

If OK proceed to "6.19.6: Incorrect Generator Current Sense Scaling".

If not OK, refer to "6.21: Incorrect Scaling Of Generator Voltage Sense" for the procedure to troubleshoot incorrect voltage sense scaling.

Incorrect Generator Current Sense Scaling

Refer to "8.19: Generator Current Sense Scale Factor" for the procedure to checkout the generator current sense scaling.

If OK proceed to "6.19.7: Incorrect Motor Current Sense Scaling".

If not OK, refer to "6.22: Incorrect Scaling Of Generator Current Sense" for the procedure to troubleshoot incorrect generator current sense scaling.

Incorrect Motor Current Sense Scaling

Refer to "8.20: Motor Current Sense" for the procedure to checkout the motor current sense scaling.

If not OK, refer to 6.23: Incorrect Scaling Of Motor Current Sense" for the procedure to troubleshoot incorrect motor current sense scaling.

6.20: Auxiliary Generator Not Properly Excited

Probable Cause

* Fault In "RUN" Relay

* Fault In "AUX" Relay

* Fault In Generator Regulator

Introduction

With reference to "4.13: Wiring Diagrams" the start logic is such that the last action item in a normal start sequence is to enable the excitation of the auxiliary generator.

If there is a problem with the "RUN" or "AUX" relays the auxiliary generator will not be excited and within nine seconds the start logic will shut the engine down. If the auxiliary generator does not produce sufficient charging voltage (48 volts DC) to energize relay SR3 in the remote junction box within nine seconds, the start logic will shut the engine down. If this happens, refer to "6.5: Engine Does Not Stay Running After A Start" for the correct troubleshooting procedure.

If there is any problem with the excitation of the auxiliary generator that allows the engine to run beyond nine seconds the charging voltage must be greater than 48 volts and the exciter must be excited.

If the problem is one of wrong regulator setting rather than no excitation refer to the locomotive prints and the service literature from the manufacturers of the auxiliary generator and exciter to troubleshoot and repair.

6.21: Incorrect Generator Voltage Sense Scale Factor

Introduction

Refer to "8.18: Generator Voltage Sense Scale Factor". If the scale factor is incorrect the correct troubleshooting procedure depends on several factors:

* Is the locomotive equipped with dynamic brakes?

* If equipped with dynamic brakes, are both scale factors incorrect?

* If equipped with dynamic brakes and only one scale factor is incorrect, which one?

With reference to "8.18: Generator Voltage Sense Scale Factor" the defect could be in one of the following areas:

* Wiring between the generator AC phases and the PT primary

* Wiring between the PT's (if the locomotive is equipped with dynamic brakes)

* Wiring between the PT (or PT's) and the scaling network

* Wiring between the scaling network and TB391

* Problem on the governor mounting panel (connection to TB391-L11)

* Defective PT

* Defective scaling network

Test Procedures

6.21.2.1: Check PT's And PT Wiring

Using the same procedure as in "8.18: Generator Voltage Sense Scale Factor", run the engine loaded in each notch and note the following signals in each notch. Signals A, B and C are AC and should be measured with an RMS reading meter; the level depends on the generator output voltage and the scale factor. To ensure the initial voltmeter setting is sufficient to measure the signal, first set it to an AC range that can read an RMS voltage equal to the DC rating of the generator (refer to 3500 Locomotive Engines Personality Module Settings, SENR5187 for this rating). Signal D is DC with a maximum value equal to the DC rating of the generator.

A-TB399-L1 with respect to TB399-L2

B-TB399-L2 with respect to TB399-L3

C-TB399-L3 with respect to TB399-L1

D-Generator Voltage.

If the locomotive is equipped with dynamic brakes, also note the following signals (RMS) in each notch. To ensure the initial voltmeter setting is sufficient to measure the signal, first set it to an AC range that can read a voltage equal to the DC rating of the generator (refer to 3500 Locomotive Engines Personality Module Settings, SENR5187 for this rating).

E-TB399-L5 with respect to TB399-L6

F-TB399-L6 with respect to TB399-L7

G-TB399-L7 with respect to TB399-L5

For there to be no fault in the PT's or PT wiring the following criteria should be met for each notch for signals A thru G (the two scale factors are defined in 3500 Locomotive Engines Personality Module Settings, SENR5187):

Locomotive Without Dynamic Brakes

A = (Dx0.74)÷(Motoring Voltage Scale Factor)

B = (Dx0.74)÷(Motoring Voltage Scale Factor)

C = (Dx0.74)÷(Motoring Voltage Scale Factor)

Locomotive With Dynamic Brakes

A = (Dx0.74)÷(DB Voltage Scale Factor)

B = (Dx0.74)÷(DB Voltage Scale Factor)

C = (Dx0.74)÷(DB Voltage Scale Factor)

E = (Dx0.74)÷(Motoring Voltage Scale Factor)

F = (Dx0.74)÷(Motoring Voltage Scale Factor)

G = (Dx0.74)÷(Motoring Voltage Scale Factor)

If one or more of the above criteria are not met then the problem is either in the PT's, or in the PT wiring. Make reference to "8.18: Generator Voltage Sense Scale Factor" and the locomotive schematics to troubleshoot the defect.

If the above criteria are met, the problem is either in the scaling network, the wiring between the scaling network and the governor mounting panel or a problem in the governor mounting panel.

6.21.2.2: Check The Scaling Network

Disconnect the scaling network from the locomotive system. Using a 6V7070 Heavy-Duty Digital Multimeter make the following impedance and diode checks:

If all the above checks pass there is no problem with the voltage sense part of the scaling network.

6.21.2.3: Check The Wiring To The Governor Mounting Panel

Locomotives Without Dynamic Brakes

Check continuity between TB399-R12 and TB391-L11. Check continuity between TB399-R9 and TB391-L9.

If any connections are not 0 ohms, refer to the locomotive schematics to troubleshoot the locomotive wiring.

Locomotives With Dynamic Brakes

Check continuity between TB399-R11 and TB391-L11 with the locomotive controls set up in motoring or load test mode.

Check continuity between TB399-R12 and TB391-L11 with the locomotive controls set up in braking mode.

Check continuity between TB399-R9 and TB391-L9.

If any connections are not 0 ohms, refer to the locomotive schematics to troubleshoot the locomotive wiring.

Locomotives With And Without Dynamic Brakes

With reference to "8.18: Generator Voltage Sense Scale Factor" remove the locomotive system wires to TB399-R12, TB391-L11 and, if necessary, TB399-R11.

Measure the impedance between each of these three wires and battery negative (-). There should be no continuity (> 2 M ohms).

If there is any low impedance connection (< 2 M ohms) troubleshoot the locomotive wiring and make any necessary repairs.

6.21.2.4: Check Governor Mounting Panel

Remove the locomotive system wire to TB391-L11. Measure the impedance between TB391-L11 and TB391-L9.

If this is 64K ohms ± 10 percent there is no problem with the locomotive governor panel.

If this is not 64K ohms ± 10 percent there is a problem with the locomotive governor panel. Proceed to "6.21.2.5: Troubleshooting Governor Mounting Panel".

6.21.2.5: Troubleshooting Governor Mounting Panel

Disconnect the J1 connector from the main electronic governor box and measure the continuity between TB391-L11 to J1/11 and between TB391-L9 to J1/9.

If one or both of these connections has no continuity, refer to "4.12: Installation Diagrams (diagram 22): to troubleshoot the panel wiring.

Check the impedance between TB391-L11 and TB391-L9. It should be an open circuit (> 2M ohms). If it is not an open circuit refer "4.12: Installation Diagrams (diagram 22)" to troubleshoot the panel wiring.

If the above two checks show the panel wiring to be defective, replace the main electronic governor box according to "8.2: Main Governor Box".

6.22: Incorrect Generator Current Sense Scale Factor

Introduction

Refer to "8.19: Generator Current Sense Scale Factor" to check the scale factor. If the scale factor is incorrect the correct troubleshooting procedure depends on several factors:

* Is the locomotive equipped with dynamic brakes?

* If equipped with dynamic brakes, are both scale factors incorrect?

* If equipped with dynamic brakes and only one scale factor is incorrect, which one?

* What is the CT location in the generator?

Some generators have the CT's located to measure the full phase current. Other generators have the CT's located to measure only part of the phase current.

With reference to "8.19: Generator Current Sense Scale Factor", the problem could be in one of the following areas:

* Traction generator fault (if the CT's measure only partial phase current)

* Wiring between the CT's and the scaling network

* Wiring between the scaling network and TB391

* Problem on the governor mounting panel (connection to TB391-L10)

* Defective CT

* Defective scaling network

Test Procedures

6.22.2.1: Test 1

Using the same procedure as "8.19: Generator Current Sense Scale Factor", run the engine loaded in each notch and measure the AC RMS current through the wire connections to points A, B, and C. This can be done either with a suitably sized clamp-on meter, or with a digital multi-meter with 1 ohm current sensing resistors. Refer to 3500 Locomotive Engines Personality Module Settings, SENR5187 for the maximum current value to determine the correct resistor wattage or ammeter size.

Point A-TB399-L9 (AMPS)

Point B-TB399-L10 (AMPS)

Point C-TB399-L11 (AMPS)

Point D-Generator Current. (Measure this using the load bank shunt).

Using a 6V7070 Heavy-Duty Digital Multimeter measure the following DC voltages:

E-TB391-L10 with respect to TB391-L9.

F-TB391-L10 with respect to TB391-L9 with the wire to TB399-R4 disconnected.

For there to be no defect the following criteria should be met. Refer to 3500 Locomotive Engines Personality Module Settings, SENR5187 for the values for the scale factors.

Group 1

A = D×(Scale Factor 1)

B = D×(Scale Factor 1)

C = D×(Scale Factor 1)

Group 2

A = F×(Scale Factor 2)

B = F×(Scale Factor 2)

C = F×(Scale Factor 2)

Group 3

A = E×(Scale Factor 3)

B = E×(Scale Factor 3)

C = E×(Scale Factor 3)

The above tests suffer from a degree of interactivity. It is easy to misinterpret the results. With this interactivity in mind, evaluate the results as follows:

* A problem with Group 1 results indicates a problem with the CT's or CT wiring.

* A problem with Group 2 results indicates a problem with the scaling network, especially in the connections:

TB399-L9

TB399-L10

TB399-L11

TB399-R7

TB399-R8

TB399-R9

TB399-R10

* A problem with Group 3 results indicates a problem with the scaling network, especially in the connections:

TB399-L9

TB399-L10

TB399-L11

TB399-R7

TB399-R8

TB399-R9

TB399-R10

TB399-R4

If there is a problem with Group 1, refer to the locomotive prints to investigate the wiring between the CT's and the scaling network. Also the generator schematics to investigate the CT's and the generator.

If there is a problem with Group 2 and 3, refer to "6.22.2.2: Test 2-Check The Scaling Network" to investigate the scaling network.

6.22.2.2: Test 2-Check The Scaling Network

Disconnect the scaling network from the locomotive system.

Using a 6V7070 Heavy-Duty Digital Multimeter make the following impedance and diode checks:

If all the above checks pass there is no problem with the current sense part of the scaling network.

6.22.2.3: Test 3-Check The Wiring To The Governor Mounting Panel

Locomotives Without Dynamic Brakes

Check continuity between TB399-R10 and TB391-L10.

Check continuity between TB399-R9 and TB391-L9.

Check continuity of the jumper between TB399-R4 and TB399-R8

If any connections are not 0 ohms, refer to the locomotive schematics to troubleshoot the locomotive wiring.

Locomotives With Dynamic Brakes

Check continuity between TB399-R10 and TB391-L10.

Check continuity between TB399-R9 and TB391-L9.

Check the dynamic brake interlock relay that connects TB399-R4 and TB399-R8.

If any connections are not 0 ohms, refer to the locomotive schematics to troubleshoot the locomotive wiring.

6.22.2.4: Test 4-Check Governor Mounting Panel

Remove the locomotive system wire to TB391-L10.

Measure the impedance between TB391-L10 and TB391-L9.

If this is 64K ohms ± 10 percent, there is not a problem with the locomotive governor panel. If this is not 64K ohms ± 10 percent, there is a problem with the locomotive governor panel, proceed to "6.22.2.5: Test 5-Troubleshooting Governor Mounting Panel".

6.22.2.5: Test 5-Troubleshooting Governor Mounting Panel

Disconnect the J1 connector from the main electronic governor box and measure the continuity between TB391-L10 to J1/10 and between TB391-L9 to J1/9.

If one or both of these connections has no continuity, refer to "4.12: Installation Diagrams (diagram 22)" to troubleshoot the panel wiring.

Check the impedance between TB391-L10 and TB391-L9. It should be an open circuit (> 2M ohms). If it is not an open circuit refer to "4.12: Installation Diagrams (diagram 22)" to troubleshoot the panel wiring.

If the above two checks show the panel wiring to be defective, replace the main electronic governor box according to "8.2: Main Governor Box".

6.23: Incorrect Scaling Of Motor Current Sense

Probable Cause

* Incorrect Transductor Excitation

* Defective Transductor

* Defective Input Module

* Defective Wheelslip Module

Introduction

This troubleshooting procedure essentially interprets the results obtained from performing the procedures outlined in "8.20: Motor Current Sense Scale Factor". The procedure assumes that the procedures outlined have already been performed and an incorrect scale factor has been confirmed.

Check For Correct Transductor Excitation

With reference to "4.12: Installation Diagrams (diagrams 11 thru 15)" and the locomotive prints check the excitation voltage to the transductors with the engine running in each notch.

Refer to the appropriate service information from the auxiliary generator manufacturers to determine normal operation.

Transductor Check

Perform the procedure outlined in "8.20.3: Transductor Check".

If OK proceed to "6.23.5: Input Module Check".

If not OK, check the wiring to the apparently defective transductor and repair if necessary. If the wiring is OK replace defective transductor.

Input Module Check

Perform the procedure outlined in "8.20.4: Input Module Test".

If OK proceed to "6.23.6: Wheelslip Module Check".

If not OK, check the wiring to the apparently defective input module and repair if necessary. If the wiring is OK replace defective input module according to "8.13: Wheelslip Module".

Wheelslip Module Check

Perform the procedure outlined in "8.20.5: Wheelslip Module Current Scaling Check".

If OK there has been an error in conducting the procedures up to this point. Start back at the beginning of "6.23: Incorrect Scaling Of Motor Current Sense".

If not OK, replace the wheelslip module according to "8.13: Wheelslip Module".

6.24: Low Pacesetter Signal

Introduction

This procedure assumes that the voltage on TB392-R6 has been measured at less than 50 Volts DC under conditions in which it should be greater than or equal to 50 Volts DC.

Probable Cause

* Truck-slide Relay Wrongly Energized

* Locomotive Wiring Problem

* Low Battery Voltage

* Wrong 24T Signal Scaling

Check Truck-Slide Relay (If Fitted)

Refer to the locomotive prints to check the status of the truck-slide relay and confirm there is no problem with it or the wiring to TB399-R5 and TB399-R6. Make any necessary repairs.

Locomotive Wiring

Check the locomotive wiring to ensure that TB399-L12 is correctly connected to battery positive (+) when in motoring mode and that TB399-R3 is connected to battery negative (-). Make any necessary repairs.

Low Battery Voltage

Measure the battery voltage. If it is less than 69.156 volts DC under charge with the engine running, the input to TB392-R6 will be less than 50 volts DC. Investigate the low battery voltage and make any necessary repairs.

Check The 24T Signal Scaling

Refer to "8.22: 24T Signal Scaling" to measure the 24T signal scale factor.

If OK an error has been made, start back at beginning of "6.24: Low Pacesetter Signal".

If not OK refer to "6.25: Incorrect 24T Signal Scaling" to troubleshoot the incorrect scale factor.

6.25: Incorrect 24T Signal Scaling

Introduction

This procedure assumes that the procedures in "8.22: 24T Signal Scaling" has been completed and an incorrect scale factor has been confirmed.

Probable Cause

* Defect In Main Mounting Group Of The Electronic Governor

* Defect In The Locomotive Wiring

* Defect In The Scaling Network

Check Main Electronic Governor

Remove the locomotive system wire (X) from TB392-R6 and measure two DC voltages on TB399-L12 (signal A) and on wire X (signal B), both with respect to TB391-L9.

Compute the ratio of (B/A).

This ratio should be 0.723 ± 10 percent with the truck slide relay de-energized. This ratio should be 0.105 ± 10 percent with the truck slide relay energized. If these ratios are still incorrect proceed to "6.25.4: Check The Locomotive Wiring".

If these ratios are now correct there is a problem in the mounting group of the main electronic governor.

6.25.3.1:

Turn off all power to the mounting group of the electronic governor.

Check the impedance between TB392-R6 and TB391-L9 on the main locomotive. This should be 64 K Ohms ± 10 percent. If it is an error has been made. Perform "8.22: 24T Signal Scaling".

If it is not 64 K Ohms ± 10 percent a problem has been confirmed on the mounting group. Disconnect the wire to Terminals 8 and 6 on the derate module mounted on the mounting group. Check the impedance between Terminals 8 and 6 on the derate module mounted on the mounting group.

This should be 64 K Ohms ± 10 percent. If it is, there is a problem with the wiring on the mounting group of the electronic governor. Refer to "4.12: Installation Diagrams (diagram 22) to troubleshoot and repair.

If it is not 64 K Ohms ± 10 percent there is a problem with the derate module. Refer to "8.4: Altitude Derate Module or 8.5: Non-Altitude Derate Module" to replace the derate module.

6.25.3.2:

Replace wire X on TB392-R6.

Check The Locomotive Wiring

Remove the other end of the locomotive system wire (X) from TB399-R5 and measure two DC voltages on TB399-L12 (signal A) and on TB399-R5, both with respect to TB391-L9.

Compute the ratio of (B/A). This ratio should be 0.723 ± 10 percent with the truck slide relay de-energized. This ratio should be 0.105 ± 10 percent with the truck slide relay energized.

If these ratios are still incorrect there is a defect in the scaling network. Replace the scaling network according to "8.12: Scaling Network".

If these ratios are now correct there is a problem with the locomotive wiring associated with wire X. Refer to the locomotive prints to troubleshoot and repair.

Replace both ends of wire X to TB392-R6 and TB399-R5.