Troubleshooting

Introduction

On the pages that follow are two lists of possible problems; Diagnosed Problems List and Undiagnosed Problems List. Before checking the list of problems, check the ECM display for any diagnostic codes. These codes aid in finding the problem (see Diagnosed Problems List).

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NOTICE
Before checking the list of problems, check the battery voltage of all electronic controls. At the power terminal connections, the required voltage measured between battery positive (B+) and battery negative (B-) is from +15 to +45 DCV. It is possible for battery voltages below +15 DCV to cause temporary failures of the electronic controls. It is possible for battery voltages above +45 DCV to cause permanent damage of the electronic controls and require correcting before troubleshooting any further. To locate the power terminal connections, refer to the following chart and the Schematics And Wiring Diagrams section.

Before replacing anything, inspect all control, component and harness connections. Loose connections could cause electrical problems. Make sure the connections are tight before testing continues.

More than one faulty component or control could cause electrical failures. Find and correct the cause of an electrical failure before making any replacements.

Identify the particular type of problem from the Problem List, then go directly to that problem. However, when beginning the procedure for that problem, start at Step 1 and follow through the step by step procedure. The Steps in a particular problem provide a definite sequence for a logical, one by one elimination of many variables. These steps are arranged in order from the more probable/easiest to check, to the less probable/more complex to check.

When the cause of the problem is found and corrected, stop the test. Do NOT continue through the complete procedure.

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When servicing or repairing electric power generation equipment, do the following: a. Make sure the unit is off-line (disconnected from utility power service and/or other generators), and either locked out or tagged DO NOT OPERATE. b. Make sure the generator engine is stopped. c. Make sure all batteries are disconnected. d. Make sure all capacitors are discharged. When power generation equipment is in operation to make tests and/or adjustments, high voltage and current are present. Make sure the testing equipment is designed for and correctly operated for the high voltage and current tests. Failure of improper test equipment presents a high voltage shock hazard to the user.

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When the engine-generator, or any source to which the engine-generator is synchronized to, is operating, voltages up to 600V are present in the control panel. Do NOT short these terminals with line voltage to ground with any part of the body or any conductive material. Loss of life or injury could result from electrical shock or injury from molten metal.

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Do NOT connect generator to a utility electrical distribution system, unless it is isolated from the system. Personal injury or death is possible by electrical feedback into the distribution system. Open and secure main distribution system switch or, if the connection is permanent, install a double throw transfer switch to prevent electrical feedback. Some generators are specifically approved by a utility to run in parallel with the distribution system and isolation is NOT required. Always check with the utility as to the applicable circumstances.

Test Instruments

Caterpillar Digital Multimeter (6V7070) Or Equivalent - is used for many of the voltage and resistance checks. Rectifiers are also checked with the special diode function. For further information about using the digital multimeter, see Special Instruction, Form No. SEHS7734.

NOTE: See the following WARNING if generator is rated over 600 volts.

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On generators with higher than 600 volts rating, do NOT use direct-reading test equipment to measure the voltage or line current, (even though the instrument has higher voltage capacity). Only use voltage and current transformers with a high voltage reading. On power circuits higher than 600 volts, insulation failure is possible on direct reading meters and present a high voltage shock to the user.

Problems

The engine control module (ECM) provides built-in diagnostic capabilities. The diagnostics are designed to make service and maintenance of the system as simple as possible. Faults that are diagnosed by the ECM are listed in the Diagnosed Problems List. Faults that are NOT diagnosed by the ECM are listed in the Undiagnosed Problems List.

Diagnosed Problems

For diagnosed problems, the diagnostic codes are displayed on the same display as the service hours, engine speed, battery voltage, engine oil pressure, and engine coolant temperature. When a diagnostic code is displayed, the arrow that indicates which of the above parameters are displayed is missing and a FLASHING "dIAG" is displayed. If several faults are present, the diagnostic codes are displayed in sequence. The diagnostic code is cleared from display by turning the engine control switch (ECS) to the OFF/RESET position. Before attempting a repair, place the ECS in the OFF/RESET position and restart the engine to see if problem recurs.

Diagnosed Problems List

Problem A - ECM Display = 01 dIAG, no magnetic speed pickup (speed sensor) signal.

Problem B - ECM Display = 02 dIAG, no oil pressure/temperature module signal.

Problem C - ECM Display = 03 dIAG, a problem with inputs from the ECS.

Problem D - ECM Display = 04 dIAG, loss of setpoints programmed into the ECM memory.

Problem E - ECM Display = 05 dIAG, engine shuts down with no shutdown command from the ECM.

Problem F - ECM Display = 06 dIAG, internal failure of ECM or unstable voltage supply.

Problem G - ECM Display = 07 dIAG, internal ECM programming switch does NOT match program.

Problem H - ECM Display = 08 dIAG, temperature probe problem.

Problem I - ECM Display = 09 dIAG, oil pressure probe problem. ECM displays high oil pressure when the engine is NOT running and has cooled down.

Problem A

ECM Display = 01 dIAG, no magnetic speed pickup (speed sensor) signal.

Procedure

STEP 1. Disconnect the speed sensor leads from terminals 1 and 7 of the ECM. Measure the resistance between the speed sensor leads. Also measure the resistance between each speed sensor lead and ground.

* Resistance between leads is between 100 and 270 ohms. Also, the resistance between each lead and ground is above 5000 ohms.

Speed sensor wiring is okay. Go to Step 2.

* Resistance is below 100 ohms.

Short circuit in wiring or sensor. Repair wiring or replace speed sensor as needed.

* Resistance is above 270 ohms.

Wire is open (broken) or connector is defective. Repair open (broken) wire or bad connection or replace speed sensor as needed.

* Resistance between sensor leads and ground is below 5000 ohms.

Speed sensor is grounded. Repair wiring harness or replace speed sensor as needed.

STEP 2. Reconnect speed sensor leads to terminals 1 and 7 of the ECM. Measure the AC voltage across terminals 1 and 7 of the ECM while cranking the engine. In order to perform this Step, a crank speed of 250 rpm or greater is required.

* Speed sensor voltage is 1.0 ACV or greater.

Attempt to start. If 01 dIAG reappears, replace speed sensor. If 01 dIAG still appears after replacing the sensor, replace ECM.

* Speed sensor voltage is below 1.0 ACV.

Adjust speed sensor gap (see Service Procedure E). If speed sensor voltage remains low, replace speed sensor.

Problem B

ECM Display = 02 dIAG, no oil pressure/temperature module signal.

NOTE: Without oil pressure protection the ECM shuts down the generator set. During troubleshooting or in an emergency situation, it is possible to operate with no oil pressure or coolant temperature protection by reprogramming the ECM (see Service Procedure A). Install oil pressure and coolant temperature gauges to give the operator an indication of engine conditions. After the problem is fixed, make sure to reprogram the ECM.

If the ECM is programmed to operate with no oil pressure and water temperature protection and the 02 dIAG occurs, it is possible the ECM does NOT reset. However, the engine continues to run. Check for loose connections or low battery voltage before replacing ECM.

Procedure

STEP 1. Measure the voltage between terminal 4 and battery negative (B-) of the ECM. Disconnect the 3 pin connector at the press/temp module and again measure the voltage between terminal 4 and battery negative (B-). Disconnect the wire from terminal 4 and again measure the voltage between terminal 4 of the ECM and battery negative (B-).

* Voltage is between 11 and 15 DCV in all cases.

The power supply is okay. Go to Step 2.

* Voltage is above 20 DCV in all cases.

Replace ECM. It is likely that the press/temp module is also damaged.

* Voltage is above 15 DCV but below 20 DCV in all cases or below 11 DCV in all cases.

Replace ECM.

* Voltage goes from below 11 DCV to between 11 and 15 DCV when the 3 pin connector is disconnected.

Replace press/temp module.

* Voltage goes from below 11 DCV to between 11 and 15 DCV when wire to terminal 4 is disconnected.

Repair grounded wiring between ECM and press/temp module.

* Voltage is above 15 DCV initially but is between 11 and 15 DCV when wire to terminal 4 is disconnected.

Repair wiring between ECM and press/temp module. If wire is shorted to battery positive (B+), failure of the press/temp module is probable and replacement is advised.

STEP 2. Reconnect any wires that were disconnected in Step 1. Measure the voltage at terminal 5 of the ECM with respect to battery negative (B-).

* Voltage is 4 to 8 DCV.

The voltage level is okay. Go to Step 3.

* Voltage is above 8 DCV.

Go to Step 4.

* Voltage is below 4 DCV.

Recheck supply voltage to the press/temp module (Step 1). If okay, disconnect wire to terminal 5 of ECM. If voltage at terminal 5 now goes above 8 DCV, replace the press/temp module. If voltage at terminal 5 remains low, replace the ECM.

STEP 3. Reconnect any wires that were previously disconnected. Disconnect the 3 pin connector at the pressure/temperature module. Measure the voltage between battery negative (B-) and pin 1 of the wiring harness connector. Also measure resistance between battery negative (B-) and pin 2 of this connector.

* Voltage is between 11 and 15 DCV and resistance is below 1 ohm.

Supply to press/temp module okay. Go to Step 5

* Voltage is below 11 DCV.

Repair wiring between ECM and press/temp module.

* Resistance is above 5 ohms.

Repair wiring between press/temp module and battery negative (B-).

STEP 4. Reconnect any wires that were previously disconnected. Disconnect the 3 pin connector at the pressure/temperature module. Measure the voltage between battery negative (B-) and pins 1 and 3 of the wiring harness connector. Also measure resistance between battery negative (B-) and pin 2 of this connector.

* Voltage at pin 1 is below 11 DCV or voltage at pin 3 is below 8 DCV.

Repair wiring between ECM and press/temp module.

* Resistance is above 5 ohms.

Repair wiring between press/temp module and battery negative (B-).

* Voltage at pin 1 is between 11 and 15 DCV. Also, voltage at pin 3 is above 8 DCV. Also, resistance is below 1 ohm.

Go to Step 5.

STEP 5. Reconnect any wires that were previously disconnected. At the pressure/temperature module, disconnect the 3 pin harness connector that goes to the engine oil pressure sensor. At the module harness connector, measure the voltage between pin A (red power wire) and pin B (yellow ground wire).

* Voltage is less than 4.5 DCV.

Repair wiring between module and pressure sensor. If a wiring problem is NOT found, replace the pressure/temperature module.

* Voltage is greater than 4.5 but less than 6.0 DCV.

Replace the engine oil pressure sensor which is located on the engine.

* Voltage is greater than 6.0 DCV.

Replace the pressure/temperature module. It is likely that the pressure sensor is also damaged.

Problem C

ECM Display = 03 dIAG, a problem with inputs from the ECS.

Procedure

The engine control switch (ECS) must connect ECM terminal 9 or 10 or 11 or 12 to battery negative (B-). If both 9 and 11 are connected to negative, auto start occurs. Any wiring error or loose connection causes an 03 dIAG code. Check ECS and wiring from ECS to ECM; repair as needed.

* Wiring and ECS check okay.

Replace the ECM.

* Wiring or ECS check bad.

Repair or replace components as necessary.

Problem D

ECM Display = 04 dIAG, loss of setpoints programmed into the ECM memory.

Procedure

To correct this problem, the ECM must be reprogrammed in a specific manner; perform the following Steps.

STEP 1. Turn the ECS to the OFF/RESET position.

STEP 2. Momentarily disconnect battery positive (B+) from the ECM and then reconnect.

STEP 3. Turn the ECS to the STOP position. Check each setpoint and reprogram if not correct. Any setpoints specified as "0" must be programmed to a different value and then reprogrammed to "0". See Service Procedure A - Programming The ECM.

STEP 4. Turn the ECS from STOP to OFF/RESET and back to STOP.

STEP 5. Check the display to see if the 04 dIAG remains.

* 04 dIAG is NOT shown on display.

Problem solved.

* 04 dIAG is shown on display.

Replace ECM.

Problem E

ECM Display = 05 dIAG, engine shuts down with no shutdown command from the ECM.

Procedure

STEP 1. Crank the engine by moving the ECS to the MANUAL position and observe the action of the governor and fuel rack. Also observe the position of the air shutoff (if so equipped). If engine does NOT crank, troubleshoot starting system according to Undiagnosed Problem 2.

* Fuel rack and governor moves in Fuel On direction, and air shutoff lever is in RUN position.

The problem is in the engine or fuel system. Refer to the engine portion of the Service Manual.

* Fuel rack does NOT move or is NOT possible to observe. Governor does NOT move in Fuel On direction or is NOT possible to observe.

Check fuel level. Fill and prime fuel system if level was low. Go to Step 2.

* Air shutoff is in the SHUTOFF position.

Reset air shutoff. Go to Step 3 if shutoff does NOT reset or if it trips during each attempt to start.

STEP 2. Remove fuse F6 (fuse between terminals R and S) from back of ECM. Prepare to use manual shutoff if needed. Crank the engine.

* Engine starts and runs.

The fuel relay (FCR) is energizing the shutoff solenoid. Check resistance between terminals S and 23. If it is below 5 ohms, go to Service Procedure B. If not, look for wiring errors that might supply voltage to shutoff solenoid. Replace if necessary.

* Engine does NOT start.

The shutoff solenoid is stuck or the fuel rack is stuck in the SHUTOFF position or solenoid is NOT correct for the application. Find the source of the problem and correct.

STEP 3. Check for another diagnostic code. If none is displayed, remove fuse F7 (between terminals T and U) from back of ECM.

* Air shutoff does NOT trip and engine starts.

The air shutoff relay (ASR) is energizing the solenoid. Check resistance between terminals U and 24 of the ECM. If it is below 5 ohms, go to Service Procedure B. If not, look for wiring errors that might supply voltage to shutoff solenoid.

* Air shutoff continues to trip.

The air shutoff is defective. See the air shutoff section of the Engine Service Manual.

* Air shutoff does NOT trip and engine does NOT start.

Check diagnostic code and return to Step 1 if code 05 dIAG remains displayed.

Problem F

ECM Display = 06 dIAG, internal failure of ECM or unstable voltage supply.

Procedure

Reset and wait 90 seconds. Restart to see if problem re-occurs. If it does, look for possible sources of electrical noise such as loose connections in supply to ECM. Install jumper between terminals D and F of the ECM. Reset and start engine.

* 06 dIAG recurs only when engine is running.

Loose connection between battery positive (B+) or battery negative (B-) to ECM remains likely. Run separate supply wires. Replace ECM if this fails to correct problem.

* 06 dIAG recurs when engine is NOT running.

Loose connection still possible but less likely. Replace ECM unless an external electrical noise source is identified.

* 06 dIAG does NOT recur.

Check crank termination relay (CTR) or fuel control relay (FCR) contacts or leave jumper (D to F) connected if battery drain is NOT a problem.

* 06 dIAG reoccurs when engine is starting and engine cranks slowly or NOT at all.

Battery voltage is low. Charge and/or replace batteries.

Problem G

ECM Display = 07 dIAG, internal ECM programming switch does NOT match program.

The 07 dIAG code indicates that the setpoint value programmed into setpoint 02 does NOT match the position of the rotary switch.

NOTE: After programming, it is possible for the 07 dIAG code to appear if the system is NOT reset.

Procedure

Turn the ECS to the OFF/RESET position. Next, turn the ECS to the RUN position.

* 07 dIAG code is NOT present.

There is no 07 dIAG code failure.

* 07 dIAG code remains present.

The value of setpoint 02 does NOT match the rotary switch position. See Service Procedure A.

Problem H

ECM Display = 08 dIAG, temperature probe problem.

Procedure

If ambient temperature is near -40°C (-40°F), use heaters to warm up the engine before startup. If temperature is warmer, check connectors between oil pressure/temperature transducer (sensor) and the temperature probe before going to Service Procedure G.

Problem I

ECM Display = 09 dlAG, ECM displays high oil pressure when the engine is NOT running and has cooled down.

Procedure

Record the oil pressure the ECM is displaying. Disconnect the harness connector of the engine oil pressure sensor. Record the oil pressure the ECM is now displaying.

* Both pressures displayed are above 965 kPa (140 psi).

In the wiring from the pressure/temperature module to the pressure sensor, check for a short between the green signal wire (pin C) and the red power wire (pin A).

* The first displayed pressure is above 480 kPa (70 psi) but below 760 kPa (110 psi). Also, the second displayed pressure is 0 kPa (0 psi).

In the harness connector, check for an open ground circuit (pin B, yellow wire).

* The first displayed pressure is 965 kPa (140 psi). Also, the second displayed pressure is 0 kPa (0 psi).

Check the pressure sensor wiring and correct as needed. If no wiring problem found, replace the engine oil pressure sensor.

* Both pressures are above 0 kPa (0 psi) but below 965 kPa (140 psi).

Replace the pressure/temperature module.

Undiagnosed Problems

Undiagnosed problems are those problems which are indicated by incorrect operation or by the fault LED's on the ECM. Undiagnosed problems are NOT indicated on the LCD display of the ECM. When an undiagnosed problem occurs, see the Undiagnosed Problems List and perform the corresponding problem procedure.

Undiagnosed Problems List

Problem 1 - Engine cranks but does NOT start or shuts down immediately after starting.

Problem 2 - Engine does NOT crank.

Problem 3 - Starting motor remains engaged or continues to run after engine has started.

Problem 4 - Engine shutdown occurs, all six LED fault indicators on the ECM FLASH.

Problem 5 - LED fault indicator on the ECM does NOT reset.

Problem 6 - Engine shutdown occurs, overcrank LED FLASHES.

Problem 7 - Engine shutdown occurs, overspeed LED FLASHES.

Problem 8 - Engine shutdown occurs, low oil pressure LED FLASHES.

Problem 9 - Engine shutdown occurs, high coolant temperature LED FLASHES.

Problem 10 - Engine shutdown occurs, emergency stop LED FLASHES.

Problem 11 - Engine shutdown occurs, reverse power LED FLASHES.

Problem 12 - No engine shutdown when a fault occurs.

Problem 13 - Engine shutdown with no LED's FLASHING or diagnostic codes shown.

Problem 14 - ACM displays all dashes "---".

Problem 15 - ACM Hz displays "LO" and voltmeter displays "0".

Problem 1

Engine cranks but does NOT start or shuts down immediately after starting.

Procedure

Look at the ECM Display.

* Overcrank LED's is ON.

Reset control and check cycle crank time and overcrank time setpoints (see Service Procedure A). Normally both times are 5 seconds or more. If engine does NOT start in 5 seconds, troubleshoot engine/fuel system/governor.

* Overcrank LED did NOT light (if off). If the engine started and then shut down, an 05 dlAG code is displayed.

Go to Diagnosed Problem E, diagnostic code 05, regardless if 05 dlAG is displayed or not.

* Some other diagnostic code is displayed.

Go to the Diagnosed Problem List and do the problem indicated by the diagnostic code.

Problem 2

Engine does NOT crank.

Procedure

STEP 1. Look at ECM Display.

* Display is completely blank regardless of the engine control switch setting.

Go to Step 2.

* All 6 LED fault indicators are ON.

Go to Undiagnosed Problem 4, all six LED fault indicators are ON.

* One or more but NOT all of the 6 LED fault indicators are FLASHING.

There is a shutdown fault. Go to the Undiagnosed Problem List and do the corresponding problem.

* A diagnostic code is displayed.

Go to the Diagnosed Problem List and do the problem indicated by the diagnostic code.

* No LED fault indicators are FLASHING and no diagnostic code is displayed.

Defect is in the starting circuit. Allow five minutes for CB2 in control panel to cool down and automatically reset. Attempt to start the engine. If engine does NOT crank go to Step 4.

STEP 2. Turn the engine control switch to Stop. Measure the voltage and check the polarity at terminals 1 and F of the ECM. With the positive meter lead on terminal F and the negative meter lead on terminal 1, the correct voltage is between +15 and +45 DCV.

* Polarity and voltage are correct.

Replace the ECM.

* Polarity is correct, but voltage level is below +15 DCV.

Check the battery voltage and check the wiring from the battery to the ECM. As needed, recharge or replace the batteries and repair the wiring. Refer to the DC Schematic in the Schematics And Wiring Diagrams section.

* Polarity is NOT correct.

Check and correct any improper connections between the battery and the ECM. Refer to the DC Schematic in the Schematics And Wiring Diagrams section. Go to Step 3.

STEP 3. Verify the corrections (fixes) of Step 2. Start the engine.

* Engine still does NOT crank and display is NOT blank.

Repeat Step 1.

* Engine starts.

The problem is corrected.

STEP 4. Look at the battery voltage displayed on the ECM Display.

* Voltage is low (1 to 20 volts).

Charge the battery or repair loose connections between battery cable terminal and battery.

* Voltage is above 20 volts.

Go to Step 5.

STEP 5. Prepare for the engine to crank. Momentarily connect a wire between terminals 1 and 5 on terminal strip (TS1).

* Engine cranks.

Go to Step 6.

* Engine does NOT crank.

Check to see if terminals 4 and 5 on TS1 are connected together with a jumper. If so, the magnetic switch (see Service Procedure D) or the pinion solenoid or the starting motor is defective. Repair or replace as required.

STEP 6. Attempt to start engine (ECS in manual) and measure voltage between ECM terminal 25 and battery negative (B-), terminal W and battery negative (B-), battery positive (B+) and battery negative (B-).

* All voltages are below 20 DCV.

Battery or wiring to ECM is defective. Repair or replace defective parts.

* Only the voltage at terminal 25 is below 20 DCV.

Check the starting motor relay (SMR) (see Service Procedure B).

* The voltage at terminals 25 and W are below 20 DCV. The battery voltage is above 20 DCV.

Replace fuse F8. Also check wiring from terminal W to battery positive (B+).

Problem 3

Starting motor remains engaged or continues to run after engine has started.

Procedure

STEP 1. Turn the engine control switch to Stop. Check the polarity at terminals 1 and F of the ECM. With the positive meter lead on terminal F and the negative meter lead on terminal 1, the correct voltage is between +15 and +45 DCV.

* Polarity is correct.

Go to Step 2.

* Polarity is NOT correct.

Check and correct any improper connections between the battery and the ECM. Refer to the DC Schematic in the Schematics And Wiring Diagrams section. Replace the ECM.

STEP 2. Check for diagnostic codes on the ECM display and go to that respective problem. If no diagnostic codes are shown, shut the engine down and check the voltage between terminals 5 and 2 (5 is positive) on terminal strip (TS1).

* Engine continues to crank and 15 DCV or more is measured.

Go to Step 3.

* Engine no longer cranks.

Check crank terminate setpoint (see Service Procedure A). If setpoint is okay, go to Diagnosed Problem A under 01 dlAG. If speed sensor signal is good and shielded wire is in good condition, replace the ECM.

* Engine continues to crank and there is less than 1 DCV between terminals 5 and 2.

Problem is in magnetic switch (see Service Procedure D) or in starting motor or pinion solenoid. Repair as required.

STEP 3. Disconnect wire No. 5 on terminal strip TS1.

* Engine no longer cranks and also the voltage between terminals 5 and 2 on terminal strip (TS1) remains above 15 DCV.

Check resistance between terminals W and 25 of the ECM. If it is below 5 ohms, go to Service Procedure B. If not, check for shorts or incorrect wiring that supplies voltage to terminal 5.

* Engine continues to crank.

Problem is in magnetic switch (see Service Procedure D) or in starting motor or pinion solenoid. Repair as required.

Problem 4

Engine shutdown occurs, and/or all six LED fault indicators on the ECM are ON.

Procedure

Make sure that the control panel lamp test switch (LTS) is NOT activated. Disconnect wires from terminal 8 of the ECM. Measure the DC voltage between battery positive (B+) and battery negative (B-) on the ECM.

* Fault LED's do NOT turn ON.

Test switch (LTS) or wiring is grounded. Correct the problem.

* Fault LED's remain ON. Battery voltage is 15 DCV or less.

Battery voltage is low. Charge battery or correct wiring problem as required.

* Fault LED's remain ON. Battery voltage is above 15 DCV.

Replace the ECM.

Problem 5

LED fault indicator on the ECM does NOT reset.

Procedure

Place the engine control switch (ECS) in the OFF/RESET position. If the LED does NOT go out, connect a jumper wire between terminal 12 on the ECM and battery negative (B-). Disconnect jumper wire.

* LED resets (goes out) when jumper wire is connected.

Problem is in ECS or wiring to the ECS. Repair as required.

* LED does NOT reset (still FLASHING).

Make sure that the fault condition no longer exists. (Example: Engine high coolant temperature LED FLASHES and engine is cool). If fault does NOT reset, replace the ECM.

Problem 6

Engine shutdown occurs, overcrank LED FLASHES.

Procedure

Turn ECS to the OFF/RESET position. If the overcrank LED does NOT go out, do Undiagnosed Problem 5. If the LED goes out, do Undiagnosed Problem 1.

Problem 7

Engine shutdown occurs, overspeed LED FLASHES.

Procedure

Turn ECS to the OFF/RESET position. If the overspeed LED does NOT go out, do Undiagnosed Problem 5. If the LED goes out, check for possible causes of overspeed. If no causes are found, check the overspeed setpoint and the ring gear teeth setpoint according to the Specifications section and Service Procedure A. Attempt to start engine by moving the ECS to the MANUAL position.

* Overspeed LED resets and engine starts and runs. Overspeed setpoint is correct.

Hold the verify switch on back of the ECM in the VERIFY position and increase speed until shutdown occurs. If shutdown speed is 75% of overspeed setpoint, the overspeed function is okay. Look for governor or system problems. If shutdown speed is incorrect, go to Service Procedure E. Replace the ECM if no speed sensor problem is found.

* Overspeed LED resets and engine starts, but overspeeds again.

If speed goes above overspeed setpoint, repair governor or system problem. If speed does NOT go high, go to Service Procedure E. Replace the ECM if no speed sensor problem is found.

* Overspeed setpoint is below specifications.

Program the correct setpoint according to Service Procedure A.

Problem 8

Engine shutdown occurs, low oil pressure LED FLASHES.

Procedure

STEP 1. Monitor the low oil pressure LED. Turn ECS to the OFF/RESET position.

* The LED does NOT go out.

Do Undiagnosed Problem 5.

* The LED goes out.

Check for possible causes of low oil pressure. If no causes are found, go to Step 2.

STEP 2. Check that the following setpoints, which are programmed in the ECM, agree with the specified setpoints: oil step speed, idle speed oil pressure shutdown and rated speed oil pressure shutdown. See the Specifications section and Service Procedure A.

* The setpoints agree.

Go to Step 3.

* The setpoints do NOT agree.

Reprogram the ECM to the specified setpoints. See Service Procedure A.

STEP 3.

NOTE: Without oil pressure protection the ECM shuts down the generator set. During troubleshooting or in an emergency situation, it is possible to operate with no oil pressure or coolant temperature protection by reprogramming the ECM (see Service Procedure A). Install oil pressure and coolant temperature gauges to give the operator an indication of engine conditions. After the problem is fixed, make sure to reprogram the ECM.

Install a reliable oil pressure gauge. Start the engine. At idle and rated speed, check to see if the gauge and ECM display are the same. If the oil pressure is low, do NOT continue. Shut the engine down and repair the problem in the engine lube system.

* Gauge and ECM display are the same.

Go to Step 4.

* Gauge and ECM display are NOT the same.

Go to Step 5.

STEP 4. At idle and rated speed, compare the measured oil pressure to the programmed setpoints.

* Pressure is less than the setpoints.

The problem is in the engine. Refer to the engine service manual.

* Pressure is the same or above the setpoints.

Replace the ECM.

STEP 5. A poor connection or short could cause the problem. Check, repair if necessary, the wiring and harness connector from the pressure/temperature module to the engine oil pressure sensor. Check if problem remains present.

* Problem is no longer present.

The harness was the cause of the problem.

* Problem remains present.

Replace the oil pressure sensor. If low oil pressure problem still exists, replace the press/temp module.

Problem 9

Engine shutdown occurs, high coolant temperature LED FLASHES.

Procedure

STEP 1. Turn ECS to the OFF/RESET position. Allow engine to cool down.

* The high coolant temperature LED does NOT go out after engine is cool.

Perform Undiagnosed Problem 5.

* The high coolant temperature LED goes out.

Check for possible causes for high coolant temperature. If no causes are found go to Step 2.

STEP 2. Check the coolant temperature setpoint programmed into the ECM. Make sure it is set to the specific value. See the Specifications section and Service Procedure A.

* The programmed coolant temperature setpoint is below the proper shutdown setpoint.

Temperature setpoint is NOT correct. Reprogram setpoint. See Service Procedure A.

* The programmed coolant temperature setpoint agrees with the proper shutdown setpoint.

Temperature setpoint is correct. Go to Step 3.

STEP 3. Install an accurate coolant temperature gauge with the sensing bulb in an area of high coolant flow, as close to temperature probe as possible.

NOTE: Without oil pressure protection the ECM shuts down the generator set. During troubleshooting or in an emergency situation, it is possible to operate with no oil pressure or coolant temperature protection by reprogramming the ECM (see Service Procedure A). Install oil pressure and coolant temperature gauges to give the operator an indication of engine conditions. After the problem is fixed, make sure to reprogram the ECM.

Start the engine and allow coolant temperature to stabilize. If necessary, apply a load to the generator.

* Temperature displayed by ECM and by gauge agree and it is above the temperature setpoint. Setpoint is correct and high coolant temperature LED remains ON.

Engine is overheating. Troubleshoot cooling system.

* Temperature displayed by ECM is 5°C (9°F) or higher than the temperature displayed by the gauge.

Check temperature probe (see Service Procedure F). If it is good, repeat test. Make sure the gauge is accurate. If ECM continues to read high, replace the pressure/temperature module.

* Temperature displayed by ECM and by gauge agree and are below the temperature setpoint.

Go to Undiagnosed Problem 5.

* Temperature displayed on the ECM is the word "HI" and the temperature on the gauge is below 98°C (208°F).

Check for shorts in wiring to the pressure/temperature module. Also check the temperature probe (see Service Procedure F).

Problem 10

Engine shutdown occurs, emergency stop LED FLASHES.

Procedure

Reset the emergency stop pushbutton by rotating the knob until it pops out. Turn the ECS to OFF/RESET position. If LED remains ON after attempting to reset, disconnect the wire from terminal 14 on the ECM.

* Emergency stop LED goes out when wire is disconnected.

Emergency stop switch is stuck closed or grounded or wire is grounded. Repair as required.

* Emergency stop LED remains ON.

Place the ECS in the OFF/RESET position and then in the MANUAL position. If LED remains ON, go to Undiagnosed Problem 5.

Problem 11

Engine shutdown occurs, reverse power LED FLASHES.

Procedure

Turn the ECS to the OFF/RESET position. If the reverse power LED does NOT go out, disconnect wire from terminal 13 on the ECM.

* Reverse power LED goes out (resets) after resetting.

Problem was reverse power fault. Control panel is okay.

* Reverse power LED goes out when wire is disconnected from terminal 13.

Reverse power relay does NOT reset. Check wiring to reverse power relay. If required, replace the reverse power relay.

* Reverse power LED remains FLASHING.

Go to Undiagnosed Problem 5.

Problem 12

No engine shutdown when a fault occurs.

Look at the ECM Display. If there is a diagnostic code displayed or a fault LED FLASHING and the engine is NOT shutdown, go to Procedure 1. If there is no diagnostic code or fault displayed, go to Procedure 2.

Procedure 1 (Code Or Fault Is Displayed)

Check the DC voltage relative to battery negative (B-) at TS1 terminal 7 and at terminals 23, S and R of the ECM. During this procedure, the engine is running with a fault LED ON.

* All voltages are above 20 DCV.

The wire from TS1 terminal 7 to solenoid is open or fuel shutoff solenoid is defective or NOT adjusted correctly. Repair as required.

* Voltage at TS1 terminal 7 is below 20 DCV. The other voltages are above 20 DCV.

The wire from TS1 terminal 7 to ECM terminal 23 is open. Repair wire or connection.

* Voltage of ECM terminal 23 and TS1 terminal 7 is below 20 DCV. The other voltages are above 20 DCV.

Check the FCR relay for stuck open contacts. Go to Service Procedure B.

* All voltages are below 20 DCV except for ECM terminal R.

Replace Fuse F6. If problem continues, check for shorted solenoid or grounded wiring. Repair as required.

* All voltages are below 20 DCV.

Connection from battery positive (B+) to ECM terminal R is defective. Repair as required.

Procedure 2 (No Code Or Fault Displayed)

Record all of the readings from the ECM display. Shut engine down and check the setpoint of the parameter that is supposed to shut the engine down. See the Specifications section and Service Procedure A.

NOTE: If setpoint 02 is programmed to 2 or 3, the engine does NOT shut down during an engine oil pressure or coolant temperature fault. See Service Procedure A.

* Readings from the display are within allowed setpoints.

There is no problem.

* Readings from the display are NOT within allowed setpoints.

Replace ECM.

Problem 13

Engine shutdown with no LED's ON or diagnostic codes shown.

Procedure

Check to make sure ECM terminal 15 is NOT receiving a signal to shutdown (connect to battery negative, B-).

* Terminal 15 connected to battery negative (B-).

Problem is in wiring, find defect and repair or replace it.

* Terminal 15 NOT connected to battery negative (B-).

If no other defects are found replace the ECM.

Problem 14

ACM displays all dashes "---".

Procedure

Disconnect the DC power to the ACM for a moment by turning the ECS to the OFF/RESET position. Start and run the engine if the dashes do NOT go away, replace the ACM.

Problem 15

ACM Hz displays "LO" and voltmeter displays "0".

Procedure

STEP 1. Make sure the AVS is NOT in the 0 position. Check AC volts connections to ACM terminals 1 and 2 to make sure the generator AC voltage is present.

* Generator AC voltage is present at terminals 1 and 2.

Go to Step 2.

* Generator AC voltage is NOT present at terminals 1 and 2.

Check fuses F9 through F14, AVS and wiring for defect. Repair or replace any defective part.

STEP 2. With the engine started measure the DC voltage between ACM terminals 5 and 12 (terminal 12 is positive). For this Step, the proper DC voltage is above 15 volts.

* DC voltage is below 15 volts.

Check batteries and charging system for cause of low batteries.

* DC voltage is above 15 volts.

Replace the ACM.

Service Procedures

Service Procedures List

* Service Procedure A - Programming the ECM.

* Service Procedure B - Relay Module.

* Service Procedure C - Programming the ACM.

* Service Procedure D - Magnetic Switch Test (24V).

* Service Procedure E - Speed Sensor Adjustment.

* Service Procedure F - Temperature Sensor Resistance.

* Service Procedure G - Verify Overspeed Shutdown.

* Service Procedure H - Verify High Coolant Temperature Shutdown.

* Service Procedure I - Verify Low Oil Pressure Shutdown.

Service Procedure A - Programming The ECM

The set points programmed into the ECM are factory set. However, the set points are changed to conform to the appropriate specifications when the ECM is moved from one engine type to another or when a special setting (usually overcrank or cycle crank) is needed.

NOTE: For the correct setpoints, always check the instruction print that is included with the EMCP. The instruction prints are:

3300 Family - 480 Volt ... 4P9990 Instructions.

3400 Family - 480 Volt ... 4P9989 Instructions.

3300 and 3400 Family - 600 Volt ... 1023597 Instructions.

Programmability

Programming Cover Location
(1) Cover.

Programming Components Location
(2) Potentiometer. (3) Rotary switch. (4) Momentary switch.

Setpoint information is stored and then used in the control strategy of the ECM. To program, perform the following:

1. Turn the ECS to the STOP position.

NOTE: Do NOT open cover (1) in a humid environment. Replace cover (1) as soon as possible.

2. Remove cover (1) on the backside of the ECM. Potentiometer (2), rotary switch (3) and momentary switch (4) are visible.

3. Note the position of rotary switch (3). See the following subject Setpoints, for the list of rotary switch positions and a description of the corresponding setpoint. Turn rotary switch (3) to the position that corresponds to the setpoint needing adjustment. The LCD display now shows the position of the rotary switch and the related data.

4. Press momentary switch (4). The data information corresponding to the position of the potentiometer FLASHES.

5. Adjust potentiometer (2) to change the FLASHING data as desired. Once the data is correct, press momentary switch (4). The data information stops FLASHING. Reprogramming of the setpoint is now complete.

6. Return the rotary switch to position 0 if the system has an energize to run fuel solenoid or position 1 if the system has an energize to stop fuel solenoid.

NOTE: The engine does NOT run when in the program mode or if the position of the rotary switch does NOT correspond to the operating mode programmed into setpoint 02. Consult Caterpillar Inc. concerning alterations to the specified setpoints for the engine.

7. Turn the ECS to the OFF/RESET position.

8. Apply a continuous bead of 6V6640 Sealant to the seal surface of cover (1). Install cover (1). Install an 8C4653 Security Seal on cover (1) to prevent unauthorized tampering.

Setpoints

NOTE: For the correct setpoints, always check the instruction print that is included with the EMCP. The instruction prints are:

3300 Family - 480 Volt ... 4P9990 Instructions.

3400 Family - 480 Volt ... 4P9989 Instructions.

3300 and 3400 Family - 600 Volt ... 1023597 Instructions.

The positions of rotary selector switch (3) and the corresponding setpoints are:

02 - Fuel System Type: This setpoint value describes the operating mode (type of fuel solenoid) of the ECM.

0 or 2 programs the ECM to operate with an energize to run (ETR) fuel solenoid.

1 or 3 programs the ECM to operate with an energize to shutdown (ETS) fuel solenoid or latching fuel solenoid.

2 or 3 programs the ECM to ignore pressure/temperature module faults: i.e. high coolant temperature, low oil pressure and module malfunction do NOT shut down the engine.

Position 02 is factory set at:

3300 and 3400 Families ... 0.

03 - Measurement Units: A setpoint value of 0 commands the ECM to display engine parameters in English units of measurement. A setpoint value of 1 displays metric units of measurement. See the Table that follows for the units of measurement for each parameter.

Position 03 is factory set at:

3300 and 3400 Families ... 0.

04 - Ring Gear Teeth: This setpoint value is the same as the number of teeth on the ring gear. The range of values are 110 to 260.

Position 04 is factory set at:

3300 Family ... 156 teeth.

3400 Family ... 113 teeth.

05 & 06 - Overspeed: The overspeed shutdown setpoint is programmed with the rotary selector switch in the 05 or 06 position. Position 05 has a range of 400 to 2890 rpm. Position 06 has a range of 2450 to 5000 rpm in increments of 10 rpm. Place the rotary selector switch in 05 or 06 position whichever corresponds with the specified overspeed shutdown setpoint. Program this position to the specified engine speed at which an overspeed shutdown occurs.

NOTE: After programming the 05 or 06 setpoint, both setpoints are the same value.

Position 05 is factory set at:

3300 and 3400 Families ... 2124 rpm.

07 - Crank Termination Speed: Once the engine speed passes this setpoint, the starting motor is no longer energized. The range is 100 to 1000 rpm in increments of 10 rpm.

Position 07 is factory set at:

3300 and 3400 Families ... 400 rpm.

08 - Oil Step Speed: Once the engine speed increases past this setpoint, then the ECM considers the engine is above the low idle condition in regard to low oil pressure shutdown. The range is 400 to 1800 rpm in increments of 10 rpm.

Position 08 is factory set at:

3300 Family ... 1125 rpm.

3400 Family ... 1350 rpm.

09 - Rated Speed Oil Pressure Shutdown: If the engine lube pressure drops below the setpoint and the engine speed exceeded the oil step speed for 9 seconds, then the ECM enters a low oil pressure shutdown condition. The range is 34 to 420 kPa (5 to 60 psi).

Position 09 is factory set at:

3300 Family ... 12 psi.

3400 Family ... 30 psi.

10 - Idle Speed Oil Pressure Shutdown: If the engine lube pressure drops below this setpoint and the engine has run for more than 9 seconds and the engine speed is below the oil step speed, then the ECM enters a low oil pressure shutdown condition. The range is 20 to 336 kPa (3 to 50 psi).

Position 10 is factory set at:

3300 and 3400 Families ... 10 psi.

11 - High Coolant Temperature Shutdown: If the engine coolant temperature has exceeded the setpoint for 10 seconds, then the ECM enters a high coolant temperature shutdown condition. The range is 95 to 120°C (203 to 248°F).

Position 11 is factory set at:

3300 and 3400 Families ... 225°F.

12 - Low Coolant Temperature Alarm: If the engine coolant temperature is less than this setpoint for two seconds, then the ECM sends an alarm signal to the annunciator module. The range is 10 to 30°C (50 to 86°F).

There is no annunciator module on 3300 or 3400 Rental Gen Sets. However position 12 is factory set at:

3300 and 3400 Families ... 70°F.

13 - Overcrank Time: Total time to start the engine (from when first asked to start until overcrank is indicated). The range is 5 to 120 seconds.

Position 13 is factory set at:

3300 and 3400 Families ... 90 seconds.

14 - Cycle Crank: The amount of time the starting motor cranks. Also, the amount of time the starting motor rests during a cycle crank. The range is 1 to 60 seconds.

Position 14 is factory set at:

3300 and 3400 Families ... 10 seconds.

15 - Cooldown: The amount of time the engine is allowed to run after initiation of a normal shutdown. The range is 0 to 30 minutes.

Position 15 is factory set at:

3300 and 3400 Families ... 5 minutes.

Service Procedure B - Relay Module

Relay Housing Location (Typical Example)
(1) Relay housing. (2) Screws.

The relay module is the housing that contains the fuses, terminals 16-27 and is part of the back of the ECM.

1. Disconnect the wire from TS1 terminal 1. Make sure there is NO voltage on the B+ terminal of the ECM. If necessary, remove some of the harness for easy accessibility. It is possible for moisture to enter the ECM when the relay housing is removed. Remove the relay housing in a dry environment. If relative humidity exceeds 60%, remove housing in an air conditioned area.

2. Remove screws (2) and washers that hold relay housing (1) to main housing. To open housing, install forcing screws in the two threaded holes. The threaded holes are on the ends of the housing flange and in the same bolt pattern as screws (2). Tighten the forcing screws. If necessary, insert a thin knife blade between relay housing (1) and the main housing. Drive it into the gap by tapping gently to break seal loose.

3. Open the housing and locate the relay or relays that need changed. Relays are labeled K1 through K7 on the PC board.

Relay Locations (Typical Example)
(3) FCR; fuel control relay K7. (4) ASR; air shutoff relay K6. (5) 2301; not used K1. (6) RR; run relay K5 (7) ENFR; engine failure relay K2. (8) SMR; starting motor relay K4. (9) CTR; crank termination relay K3.

4. Remove the relay clip and pull the relay straight out.

5. Do the following Relay Performance Test:

Check continuity with ohmmeter as follows:

A. With NO power on terminals 7 and 8, the correct resistance between terminals 1 and 5 is 1 ohm or less. The correct resistance between terminals 2 and 6 is 1 ohm or less. The correct coil resistance between terminals 7 and 8 is 140 to 180 ohms.

B. Apply 12 volts DC to terminals 7 and 8. The correct resistance between terminals 3 and 5 is 1 ohm or less. The correct resistance between terminals 4 and 6 is 1 ohm or less. The correct resistance between any other pairs of terminals is 100k ohm or more.

6. Replace the relay if it fails this test. Install the relay clip.

7. Check the connector going from the main housing to the relay PC board to make sure it is inserted properly.

8. If replacing the relay does NOT fix problem or if the relay is NOT defective, replace the entire relay module.

9. Clean and apply 6V1541 Primer to both housings' sealing surface.

10. Apply a continuous bead of 6V6640 Sealant to the main housing sealing surface.

11. Install relay housing (1) on the main housing and fasten with original washers and screws (2).

12. Reconnect the wires that were removed.

Service Procedure C - Programming The ACM

Switch S1 is factory set at:

3300 Family - 480 Volt ... position 8.

3400 Family - 480 Volt ... position 10.

3300 and 3400 Family - 600 Volt ... position 6.

Switch S2 is factory set at:

3300 and 3400 Families ... position 0.

The AC meter module (ACM) is factory set to display AC currents with the factory supplied current transformers (CT's). If the CT's are replaced with CT's having another ratio, reprogram the ACM.

ACM Programming Cover Location
(1) Cover.

ACM Programming Components Location - Typical Example
(2) S2 switch. (3) S1 switch. (4) R6.

The ACM is programmed using two 16 position switches, S2 (2) for voltage and S1 (3) for current, to accommodate various voltmeter ranges and CT ratios. These switches are located under the access cover (1) in the rear of the ACM. The charts list the switch positions that correspond to the different voltmeter ranges and current transformer (CT) ratios used.

It is possible for moisture to enter the ACM when the access cover is removed. Remove the cover in a dry environment. Open this cover in an air conditioned area if relative humidity exceeds 60%. If necessary, remove the ACM from the panel for programming.

To program, remove cover and turn S1 and S2 to the positions indicated in the table. Make sure that the external jumper is also connected to the terminals indicated in the table. Do NOT adjust the two calibration potentiometers to the right of S1 and S2. These are factory set to calibrate the ACM against an accurate standard. When paralleling two generator sets, it is possible the voltage readings are different. In this case the upper potentiometer R6(4) is adjusted so that both voltage displays read the same.

After programming the ACM, replace cover (1). Use a continuous bead of 6V6640 Sealant to seal the cover.

Service Procedure D - Magnetic Switch Test (24V)

Magnetic Switch Location

1. Disconnect jumper wire between terminals 4 and 5 of terminal strip (TS1). Measure resistance between terminal 5 and terminal 2. The correct resistance is 26 to 33 ohms. If resistance is incorrect, replace the defective magnetic switch. If okay, go to Step 2.

2. Disconnect cable going from the pinion solenoid to the starting motor.

3. Connect a DC voltmeter: positive to terminal 24 and negative to terminal 25 on terminal strip (TS1).

4. Connect a wire from terminal 1 to terminal 5 on terminal strip (TS1). The correct voltmeter reading changes from approximately 24 DCV to approximately 2 DCV. If voltage exceeds 2 volts, replace magnetic switch. Disconnect this wire immediately after the voltage is measured (no more than 10 seconds).

5. If the switch passes the requirements of Step 1 and 4, it is working properly. Reconnect wires and cables that were removed in this procedure.

Service Procedure E - Speed Sensor Adjustment

Magnetic Pickup
(1) Clearance dimension. (2) Locknut.

1. Remove the magnetic pickup from the engine flywheel housing and turn the flywheel until a gear tooth is directly in the center of the threaded opening for the magnet pickup. Install the magnetic pickup again in the threads of the flywheel housing.

2. Turn (by hand) in a clockwise direction until the end of the magnetic pickup just makes contact with the gear tooth. Now turn the magnetic pickup back out 1/2 turn (180° in the counterclockwise direction) to get the correct air gap [clearance dimension (1)]. Now tighten locknut (2) to a torque of 45 ± 7 N·m (33 ± 5 lb ft).

NOTE: Do NOT let the magnetic pickup turn while locknut (2) is tightened.

Service Procedure F - Temperature Sensor Resistance

Coolant Temperature Sensor
(1) Connectors to pressure/temperature module.

The resistance value of the sensor corresponds to the surrounding temperature. This test requires that the sensor is at room temperature.

1. Disconnect connectors (1).

2. There is one electrical connection in each connector (1). Measure the resistance between connectors (1). Make sure to make good contact to the connector pins.

3. Compare the measured resistance with that listed in the above chart.

* If the resistance values do NOT agree, check connectors (1) and repair any bad connections. If connectors are okay, replace the coolant temperature sensor.

* If the resistance values agree, check the mating connectors at the pressure/temperature module. If connectors are okay, replace the pressure/temperature module.

Service Procedure G - Verify Overspeed Shutdown

Back Of ECM
(1) Overspeed verify switch.

The ECM allows service personnel to verify (check) that the engine overspeed protection is functioning. Actual overspeeding of the engine is NOT required. Activation of the overspeed verify switch reduces the overspeed setpoint to 75% of the value programmed in the ECM. Therefore the overspeed verify speed is less than rated engine speed.

1. Operate the engine at rated speed. Monitor the fuel control solenoid (and the air shutoff solenoid, if equipped).

2. Press and hold overspeed verify switch (1). Release the switch after the engine stops.

3. Check that the fuel control solenoid (and the air shutoff solenoid, if equipped) cause the engine to shutdown. Also, check that the overspeed LED, on the ECM, is FLASHING.

4. Turn the ECS to the OFF/RESET position.

Service Procedure H - Verify High Coolant Temperature Shutdown

High Coolant Temperature Test Harness C1 = Connector Housing 7N9737. C2 = Connector Housing 7N9738. R = 1000 ohm ten turn potentiometer.

This procedure enables service personnel to verify (check) that the engine high coolant temperature protection is functioning. Substituting a variable resistor (potentiometer) for the temperature sensor, allows testing of the circuit without overheating the engine.

1. Determine the setpoint for high coolant temperature shutdown. See Service Procedure A.

2. Turn the ECS to the OFF/RESET position.

3. Disconnect the two harness connectors at the temperature probe. Set R to 1000 ohms. Connect the test harness to the disconnected vehicle harness connectors.

4. Start the engine. Depress the display hold switch when the engine coolant temperature is displayed. The correct displayed temperature is approximately 88°C (189°F).

5. Slowly adjust R until the displayed temperature is the same as the setpoint temperature (of step 1).

6. When the displayed and setpoint temperature are the same, the engine shuts down. Check that the fuel control solenoid caused the engine shutdown. Also, check that the overtemperature LED, on the ECM, is FLASHING.

7. Turn the ECS to the OFF/RESET position.

Service Procedure I - Verify Low Oil Pressure Shutdown

Low Oil Pressure Test Harness A = Socket A 8T8730. B = Socket B 8T8730. C = Socket C 8T8730. C1 = Connector 8T8731. R = Potentiometer, 1000 ohm, ten turn. NOTE: Socket C connects to the wiper of potentiometer R.

This procedure enables service personnel to verify (check) that the low engine oil pressure protection is functioning. This procedure controls the oil pressure signal to the pressure/temperature module without affecting the engine lubrication system. Engine shutdown is verified at idle speed and rated speed.

Idle speed oil pressure shutdown occurs when: the engine speed is less than the oil step speed value and the engine oil pressure is less than the idle speed oil pressure shutdown value. Rated speed oil pressure shutdown occurs when: the engine speed is greater than the oil step speed value and the engine oil pressure is less than the rated speed oil pressure shutdown value.

1. Determine the programmed ECM setpoint for: oil step speed, idle speed oil pressure shutdown and rated speed oil pressure shutdown. See Service Procedure A.

2. Turn the ECS to the OFF/RESET position.

3. Disconnect the engine oil pressure sensor connector from the pressure/temperature module. Connect the test harness to the pressure/temperature module connector.

4. Turn the ECS to the AUTO position. Monitor the engine oil pressure on the ECM display. Adjust potentiometer R until the pressure displayed is greater than the idle speed oil pressure shutdown value, but less than 345 kPa (50 psi).

NOTE: The ECM displays an 09 dlAG code, when the sensed oil pressure is greater than 345 kPa (50 psi) and the engine is NOT running. If an 09 dlAG code is present, clear it. To clear the diagnostic code, decrease the sensed oil pressure by adjusting potentiometer R and then turn the ECS switch to the OFF/RESET position.

5. Start and run the engine at idle speed. Keep the engine speed below the oil step speed setpoint.

6. Lower the oil pressure displayed on the ECM by slowly adjusting potentiometer R.

NOTE: The engine shuts down when the oil pressure decreases below the setpoint for idle speed oil pressure shutdown.

7. Verify that shutdown occurs when the displayed engine oil pressure is the same as (or slightly less than) the setpoint for idle speed oil pressure shutdown. Verify that the low oil pressure LED, on the ECM, is FLASHING.

8. Turn the ECS to the OFF/RESET position.

9. Turn the ECS to the AUTO position. Monitor the engine oil pressure on the ECM display. Adjust potentiometer R until the pressure displayed is greater than the rated speed oil pressure shutdown value, but less than 345 kPa (50 psi).

NOTE: The ECM displays an 09 dlAG code, when the sensed oil pressure is greater than 345 kPa (50 psi) and the engine is NOT running. If an 09 dlAG code is present, clear it. To clear the diagnostic code, decrease the sensed oil pressure by adjusting potentiometer R and then turn the ECS switch to the OFF/RESET position.

10. Start and run the engine at rated speed. Keep the engine speed above the oil step speed setpoint.

11. Lower the oil pressure displayed on the ECM by slowly adjusting potentiometer R.

NOTE: The engine shuts down when the oil pressure decreases below the setpoint for rated speed oil pressure shutdown.

12. Verify that shutdown occurs when the displayed engine oil pressure is the same as (or slightly less than) the setpoint for rated speed oil pressure shutdown. Verify that the low oil pressure LED, on the ECM, is FLASHING.

13. Turn the ECS to the OFF/RESET position to clear the ECM.

14. Remove the test harness. Reconnect the engine oil pressure sensor to the pressure/temperature module.