The engine is equipped with a Variable Nozzle Turbocharger (VNT). The VNT provides compressed air for use by the engine and by the Aftertreatment Regeneration Device (ARD).
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| Illustration 1 | g01288270 |
Turbochargers (1) Turbocharger on C7 engines with less than 330 hp (2) Turbocharger on C7 engines with 330 hp or more, and on C9 engines | |
The following information applies to the turbochargers on these engines:
Turbochargers on C7 engines with less than 330 hp have a hydraulic actuator and a speed sensor. The actuator receives a pulse width modulated command (PWM) from the ECM. The actuator uses pressurized engine oil to convert the PWM command into movement of the vanes inside the turbine housing. Movement of the vanes causes the boost pressure to change. The speed sensor creates a speed signal for the ECM.
Turbochargers on C7 engines with 330 hp or more, and on C9 engines have an electronic actuator and a speed sensor. The actuator receives electrical power that is provided by the OEM via a breakout on the engine harness. The actuator receives commands from the ECM via the CAN data link. The actuator converts the commands into movement of the vanes inside the turbine housing. Movement of the vanes causes the boost pressure to change. The actuator sends status information to the ECM via the CAN data link. The speed sensor creates a speed signal for the ECM.
Table 1 lists the diagnostic trouble codes that apply to these turbochargers:
| List of Diagnostic Trouble Codes | ||
|---|---|---|
| J1939 Code | Description | Diagnostic Code Information |
| 103-8 (1) (2) | Engine Turbocharger 1 Speed : Abnormal Frequency, Pulse Width, or Period | There is a problem with the speed signal from the turbocharger. The code is logged. A snapshot is taken. Engine power is derated. The active code is cleared if the speed signal returns to normal. |
| 103-16 (1) (2) | Engine Turbocharger 1 Speed : High - Moderate Severity (2) | The turbocharger speed has exceeded the high limit. The code is logged. A snapshot is taken. Engine power is derated. The active code and the derate are cleared when the speed of the turbocharger goes below the high limit. |
| 641-4 (2) | Engine Turbocharger Variable Geometry Actuator #1 : Voltage Below Normal | The electrical power for the actuator is too low. The code is logged. Engine power is derated. The active code and the derate are cleared if the voltage returns to the acceptable range. |
| 641-5 (1) | Engine Turbocharger Variable Geometry Actuator #1 : Current Below Normal | The current flow through the circuit for the PWM command is below the minimum range. This problem can be caused by an open circuit or by a short to ground on the "PWM -" wire. The code is logged. A snapshot is taken. Engine power is derated. The active code and the derate are cleared if the current flow returns to the acceptable range. |
| 641-6 (1) | Engine Turbocharger Variable Geometry Actuator #1 : Current Above Normal | The current flow through the circuit for the PWM command is above the acceptable range. This problem can be caused by the following conditions: A short to + Battery on the "PWM +" or "PWM -" wire A short to ground on the "PWM +" wire A short circuit between the "PWM +" wire and the "PWM -" wire A short circuit inside the actuator The code is logged. A snapshot is taken. Engine power is derated. The active code and the derate are cleared if the current flow returns to the acceptable range. |
| 641-7 (2) | Engine Turbocharger Variable Geometry Actuator #1 : Not Responding Properly | The position of the movable vanes is incorrect. The code is logged. A snapshot is taken. Engine power is derated. The active code and the derate are cleared if the actuator returns to normal operation. |
| 641-9 (2) | Engine Turbocharger Variable Geometry Actuator #1 : Abnormal Update Rate | There has been no communication between the actuator and the ECM for at least one second. The code is logged. A snapshot is taken. Engine power is derated. The active code and the derate are cleared if communication is restored for at least 4 seconds. This code is caused by one of the following conditions: Loss of electrical power to the actuator A problem with the CAN data link A problem with the actuator |
| 641-12 (2) | Engine Turbocharger Variable Geometry Actuator #1 : Failure | There is an internal problem with the actuator. The code is logged. Engine power is derated. The active code and the derate are cleared if the actuator returns to normal operation. |
| 641-14 (2) | Engine Turbocharger Variable Geometry Actuator #1 : Special Instruction | The CAN data link is OK. However, some of the messages on the CAN data link from the actuator to the ECM have been incorrect or missing for at least 10 seconds. The code is logged. Engine power is derated. The active code and the derate are cleared if complete communication is restored. This code is caused by a problem with the actuator. |
| ( 1 ) | This code applies to turbochargers on C7 engines with less than 330 hp. |
| ( 2 ) | This code applies to turbochargers on C7 engines with 330 hp or more, and to turbochargers on C9 engines. |
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| Illustration 2 | g01332441 |
Schematic for turbochargers on C7 engines with less than 330 hp | |
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| Illustration 3 | g01332447 |
Schematic for turbochargers on C7 engines with more than 330 hp and for turbochargers on C9 engines | |
Test Step 1. Determine the Diagnostic Code
- Establish communication between the Caterpillar Electronic Technician (Cat ET) and the engine ECM. The communication adapter must be communicating on both data links in order to perform this procedure. Refer to Troubleshooting, "Electronic Service Tools" for additional information, if necessary.
Note: The engine must be at idle speed for at least 30 seconds in order for all of the codes to be reported.
- Determine the code that is present. Note the time of occurrence of the code.
- Interview the operator. Determine if the operator felt an engine performance problem that occurred with the logged code.
Troubleshoot the logged code only if the code can be related to an engine performance problem. Otherwise, clear the logged code.
Expected Result:
A code for the turbocharger is active or logged. If the code is logged, the logged code relates to an engine performance problem.
Results:
- 641-5 code - Proceed to Test Step 2.
- 641-6 code - Proceed to Test Step 3.
- 641-4 code - Proceed to Test Step 4.
- 103-8 code - Proceed to Test Step 5.
- 641-9 code - Proceed to Test Step 6.
- 103-16 code - Proceed to Test Step 8.
- 641-14 code - Proceed to Test Step 9.
- 641-7 or 641-12 - Perform the following repair procedure:
Repair:
- Clear the logged code. Cycle power to the engine. Start the engine. Allow the engine idle for at least 30 seconds.
- Check for the logged code again. If the code is logged again, replace the turbocharger. If the code is not logged again, return the vehicle to service.
STOP
Test Step 2. Determine the Cause of the Low Current Flow in the Circuit for the PWM Command
Carefully following this procedure is a good way to identify the root cause of an intermittent wiring problem.
- Perform a visual inspection of the wiring between the P2 connector and the actuator. Look for the following problems:
- Damage that is caused by excessive heat
- Damage that is caused by chafing
- Improper routing of wiring
- Damaged insulation
- Loose connectors or damaged connectors
- Moisture on the connectors or the wiring
Repair any problems. Continue with this procedure, if necessary.
- Damage that is caused by excessive heat
- Perform a pull test on each wire that relates to the turbochargers electrical circuits. Pull on each wire in order to verify that each wire is properly connected to each terminal and that each terminal is inserted into the connector.
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| Illustration 4 | g01287975 |
P2 wiring for the PWM command for the turbocharger | |
- Disconnect the P2 connector. Inspect terminals P2-32 and P2-44.
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| Illustration 5 | g01288389 |
P2 terminals for the PWM command | |
- Connect an ohmmeter to terminals P2-32 and P2-44.
- Monitor the ohmmeter while you wiggle the wiring between the P2 connector and the actuator. Be sure to wiggle the wiring near each connector.
Note: The correct resistance for the actuator is between 3.4 and 4.2 Ohms.
Expected Result:
There is an intermittent open circuit in the wiring for the PWM command.
Results:
- There is an intermittent open circuit in the wiring for the PWM command. -
Repair: Repair the wiring, when possible. Replace parts, if necessary.
STOP
- There is an open circuit. The problem is not intermittent. -
Repair: Perform the following procedure:
- Refer to Illustration 2. There are four wires in the circuit for the PWM command. Check the continuity of each wire. Pay particular attention to the electrical connectors. Repair any problems.
If all of the wires have continuity, connect all of the connectors except the P2 connector.
- Measure the resistance between terminal P2-44 and engine ground. The correct reading is an open circuit.
Repair the wiring, if necessary. Otherwise, continue with this procedure.
- Disconnect the engine harness connector from the actuator. Measure the resistance of the actuator. The correct resistance is between 3.4 and 4.2 Ohms.
Replace the turbocharger if the actuators resistance reading is incorrect.
STOP
- Refer to Illustration 2. There are four wires in the circuit for the PWM command. Check the continuity of each wire. Pay particular attention to the electrical connectors. Repair any problems.
Test Step 3. Determine the Cause of the High Current Flow in the Circuit for the PWM Command
Carefully following this procedure is a good way to identify the root cause of an intermittent wiring problem.
- Perform a visual inspection of the wiring between the P2 connector and the actuator. Look for the following problems:
- Damage that is caused by excessive heat
- Damage that is caused by chafing
- Improper routing of wiring
- Damaged insulation
- Loose connectors or damaged connectors
- Moisture on the connectors or the wiring
Repair any problems. Continue with this procedure, if necessary.
- Damage that is caused by excessive heat
- Perform a pull test on each wire that relates to the turbochargers electrical circuits. Pull on each wire in order to verify that each wire is properly connected to each terminal and that each terminal is inserted into the connector.
| | |
| Illustration 6 | g01287975 |
P2 wiring for the PWM command for the turbocharger | |
- Use 7X-1710 Multimeter Probes to connect an ohmmeter to terminals P2-32 and P2-44.
- Measure the resistance between the points that are listed in Table 2. Wiggle the wiring between the P2 connector and the actuator as you take each measurement.
Show/hide table
Table 2 Resistance Measurements For a 641-6 Code Point Point Acceptable Resistance Value P2-44 +Battery Open circuit P2-44 Engine ground Open circuit P2-32 +Battery Open circuit P2-32 Engine ground Open circuit P2-44 P2-32 Between 3.4 Ohms and 4.2 Ohms
Expected Result:
At least one of the resistance measurements is incorrect.
Results:
- Incorrect resistance to the +Battery or engine ground - Identify the cause of the short circuit. Make the necessary repairs.STOP
- Incorrect resistance for the coil. -
Repair: Disconnect the engine harness connector from the actuator. Measure the resistance between the terminals on the electrical connector for the actuator. The correct reading is between 3.4 and 4.2 Ohms.Replace the turbocharger if the actuators resistance is incorrect.If the resistance of the actuator is correct, there is a short circuit between the wires for the PWM command. Repair the wiring.
STOP
Test Step 4. Check the Electrical Power for the Actuator
Refer to Illustration 3. The truck wiring harness provides the +Battery to the engine wiring harness. The connectors that connect the truck wiring harness to the engine wiring harness are above the engine ECM.
Note: Carefully following this procedure is a good way to identify the root cause of an intermittent wiring problem.
- Carefully check the truck wiring harness for the following problems:
- Tripped circuit breaker or blown fuse
- Disconnected connectors
- Damaged wiring
Determine the root cause of the problem if the circuit breaker is tripped or the fuse is blown. Continue with this procedure if the circuit breaker is not tripped and the fuse is OK.
- Tripped circuit breaker or blown fuse
- Use 7X-1710 Multimeter Probes to determine the voltage at the engine harness connector for the truck wiring harness. Wiggle the truck wiring harness and the connectors on the truck wiring harness while you take the voltage measurement.
Expected Result:
Battery voltage is not at the engine harness connector.
Results:
- Battery voltage is not at the engine harness connector. -
Repair: Determine the cause of the missing voltage. Make the necessary repairs to the truck wiring harness.
STOP
- Battery voltage is at the engine harness connector. -
Repair: Use 7X-1710 Multimeter Probes to check for battery voltage at the harness connector for the actuator. Wiggle the engine harness and connectors while you take the voltage measurement.If the voltage is not equal to the battery voltage, repair the engine harness. Replace parts, if necessary.If the voltage at the engine harness connector for the actuator is OK, replace the turbocharger.
STOP
Test Step 5. Determine the Cause of the Incorrect Speed Signal From the Turbocharger
Carefully following this procedure is a good way to identify the root cause of an intermittent wiring problem.
- Perform a visual inspection of the wiring between the P2 connector and the turbochargers speed sensor. Look for the following problems:
- Damage that is caused by excessive heat
- Damage that is caused by chafing
- Improper routing of wiring
- Damaged insulation
- Loose connectors or damaged connectors
- Moisture on the connectors or the wiring
Repair any problems. Continue with this procedure, if necessary.
- Damage that is caused by excessive heat
- Perform a pull test on each wire that relates to the turbochargers speed signal. Pull on each wire in order to verify that each wire is properly connected to each terminal and that each terminal is inserted into the connector.
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| Illustration 7 | g01288515 |
P2 wiring for the turbochargers speed signal | |
- Use 7X-1710 Multimeter Probes to measure the resistance between the points that are listed in Table 2. Wiggle the wiring between the P2 connector and the turbochargers speed sensor as you take each measurement.
Show/hide table
Table 3 Resistance Measurements For a 103-8 Code Point Point Acceptable Resistance Value P2-24 Terminal "1" on the engine harness connector for the turbochargers speed sensor Less than five Ohms P2-34 Terminal "2" on the engine harness connector for the turbochargers speed sensor Less than five Ohms P2-24 Engine ground Open Circuit P2-34 Engine ground Open circuit
Expected Result:
At least one of the resistance measurements is incorrect.
Results:
- High resistance between the electrical connectors - Identify the cause of the problem. Make the necessary repairs.STOP
- Incorrect resistance to engine ground. -
Repair: Identify the cause of the problem. Make the necessary repairs.
STOP
- All of the resistance measurements are correct. -
Repair: Replace the turbocharger.
STOP
Test Step 6. Check the Electrical Power for the Actuator
Refer to Illustration 3. The truck wiring harness provides the +Battery to the engine wiring harness. The connectors that connect the truck wiring harness to the engine wiring harness are above the engine ECM.
Note: Carefully following this procedure is a good way to identify the root cause of an intermittent wiring problem.
- Carefully check the truck OEM wiring installation for the following problems:
- Tripped circuit breaker or blown fuse
- Disconnected connectors
- Damaged wiring
Determine the root cause of the problem if the circuit breaker is tripped or the fuse is blown. Continue with this procedure if the circuit breaker is not tripped and the fuse is OK.
- Tripped circuit breaker or blown fuse
- Use 7X-1710 Multimeter Probes to determine the voltage at the engine harness connector for the truck wiring harness. Wiggle the truck wiring harness and the connectors on the truck wiring harness while you take the voltage measurement.
Expected Result:
Battery voltage is not at the engine harness connector.
Results:
- Battery voltage is not at the engine harness connector. -
Repair: Determine the cause of the missing voltage. Make the necessary repairs to the truck wiring harness.
STOP
- Battery voltage is at the engine harness connector. -
Repair: Use 7X-1710 Multimeter Probes to check for battery voltage at the engine harness connector for the actuator. Wiggle the engine harness and connectors while you take the voltage measurement.If the voltage is not equal to the battery voltage, repair the engine harness. Replace parts, if necessary.
If the voltage at the engine harness connector for the actuator is OK, proceed to Test Step 7.
Test Step 7. Check the CAN Data Link Between the Actuator and the Engine ECM
Note: Carefully following this procedure is a good way to identify an intermittent problem.
- Perform a visual inspection of the wiring between the P2 connector and the actuator. Look for these problems:
- Damage that is caused by excessive heat
- Damage that is caused by chafing
- Improper routing of wiring
- Damaged insulation
- Loose connectors or damaged connectors
- Moisture on the connectors or the wiring
Repair any problems. Continue with this procedure, if necessary.
- Damage that is caused by excessive heat
- Pull on each wire that is associated with the data link. This pulling verifies that each wire is properly attached to each terminal and that each terminal is properly inserted into the connector.
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| Illustration 8 | g01288134 |
P2 wiring for the CAN data link | |
Note: The termination resistor is located near the engine ECM.
- Disconnect the negative terminal from the battery.
- Use 7X-1710 Multimeter Probes to measure the resistance between the points that are listed in Table 2. Wiggle the wiring between the P2 connector and the turbochargers speed sensor as you take each measurement.
Show/hide table
Table 4 Resistance Measurements for a 641-9 code Point Point Acceptable Resistance Value P2-11 P2-12 Between 56 Ohms and 64 Ohms P2-11 Engine ground Open circuit P2-12 Engine ground Open circuit P2-12 Terminal 2 on the engine harness connector for the actuator Less than five Ohms P2-11 Terminal 4 on the engine harness connector for the actuator Less than five Ohms
Expected Result:
At least one of the resistance measurements is incorrect.
Results:
- Incorrect resistance between P2-11 and P2-12 - There is a problem with the termination resistors.
Repair: A termination resistor is missing if the resistance across the data link is greater than 64 Ohms. Determine the cause of the missing termination resistor. Make the necessary repairs.The acceptable resistance measurement of each termination resistor is between 108 and 132 Ohms. Refer to Illustration 3 for the terminals on the actuators connector that relate to the termination resistor that is inside the actuator. Replace the turbocharger if the termination resistor inside the actuator has incorrect resistance.There is a short circuit if the resistance across the data link is less than 56 Ohms. Determine the cause of the low resistance. Make the necessary repairs.
STOP
- Incorrect resistance between a P2 terminal and the harness connector for the actuator. - There is an open circuit in the CAN data link between the electrical connectors.
Repair: Determine the cause of the open circuit. Make the necessary repairs.
STOP
- Incorrect resistance to engine ground - There is a short circuit between a wire for the CAN data link and engine ground.
Repair: Determine the cause of the short circuit. Make the necessary repairs.
STOP
- All of the resistance measurements are correct. -
Repair: Replace the turbocharger.
STOP
Test Step 8. Determine the Cause of the Turbochargers Overspeed
Note: Low ambient temperature during an engine start can cause insufficient engine oil for the actuator.
- Note the time of occurrence of the overspeed event. Determine if the ambient temperature was low. Clear the logged code and return the vehicle to service if the ambient temperature was low and the overspeed event occurred. Otherwise, continue with this procedure.
- Check the engine oil level.
Expected Result:
The engine oil level is OK.
Results:
- Yes - The engine oil level is OK. -
Repair: Replace the turbocharger.
STOP
- No - The engine oil level is not OK. -
Repair: Service the engine oil.
STOP
Test Step 9. Replace the Turbocharger
Replace the turbocharger.
Expected Result:
The turbocharger was replaced.
Results:
- Yes - The turbocharger was replaced.STOP