C9 Agricultural Engine for Challenger Tractors Caterpillar

Use this procedure to troubleshoot the electrical system if a problem is suspected with a supply circuit or if any one of the diagnostic codes in Table 1 is active or easily repeated.

System Operation

The ECM supplies a regulated voltage of 5.0 ± 0.2 VDC to the following sensors:

• Fuel pressure sensor

• Engine oil pressure sensor

• Injection actuation pressure sensor

• Atmospheric pressure sensor

• Intake manifold pressure sensor

• L track accumulator pressure sensor

• R track accumulator pressure ensor

The ECM supplies a regulated voltage of 8.0 ± 0.4 VDC to the coolant level sensor (if equipped).

The supply voltage for the sensors is routed from the ECM to terminal A of each sensor connector. The sensor return for the sensors is routed from the ECM to terminal B of each sensor connector. The ECM provides short circuit protection for the internal power supply. A short circuit to the battery will not damage the internal power supply.

If a 10 code is logged, this indicates that the 5 volt supply is not available at the sensor connector. During normal engine operation, each of the signals from the pressure sensors fluctuate slightly. When the 5 volt supply becomes unavailable at the pressure sensor connector, the signal from that sensor floats to a midrange value. The signal will not fluctuate. If the signal from the sensor remains abnormally steady for more than 30 seconds, the ECM will activate this code.

Note: The sensors are not protected from overvoltage. A short from the supply line to the +Battery may damage the sensors. If any of the 3 diagnostic codes are active, it is possible that a sensor has been damaged. Repair the sensor supply and check for any active sensor diagnostic codes in order to determine if a sensor has failed.

Illustration 1	g01374466
Schematic for the sensor supply circuit

Test Step 1. Inspect the Electrical Connectors and the Wiring

1. Remove electrical power from the ECM.

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Illustration 2	g01374528
Locations of the components that are associated with the sensor supply circuits Component locations for the analog sensors (typical left side engine view) (1) Intake manifold pressure sensor (2) Atmospheric pressure sensor (3) Fuel pressure sensor (4) Injection actuation pressure sensor (5) Engine oil pressure sensor (6) J2/P2 ECM connector (7) J1/P1 ECM connector

2. Thoroughly inspect the connectors for sensors (1 through 5). Also, thoroughly inspect connectors (6) and (7) .

   Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.

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Illustration 3	g01380573
Terminal locations at the P1 ECM connector for the sensor supply (P1-2) 5 V Sensor supply (P1-3) Sensor return (P1-4) 8 V Sensor supply (P1-5) Sensor return (P1-18) Sensor return

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Illustration 4	g01340136
Terminal locations at the P2 ECM connector for the sensor supply (P2-17) Sensor return (P2-54) Sensor return (P2-72) 5 V Sensor supply (P2-80) 5 V Sensor supply

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Illustration 5	g01159881
Terminal locations at the sensor connector for the sensor supply (Terminal A) 5 V or 8 V sensor supply (Terminal B) Sensor return (Terminal C) Sensor signal

3. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connectors that are associated with the circuit.

4. Check the allen head screw for each of the ECM connectors for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.

5. Check the harness and wiring for abrasion and for pinch points from the sensors back to the ECM.

Expected Result:

All connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion and of pinch points.

Results:

• OK - The harness and connectors appear to be OK. Proceed to Test Step 2.

• Not OK - There is a problem with the connectors and/or wiring.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.

  STOP

Test Step 2. Check for Active Diagnostic Codes

1. Connect Caterpillar Electronic Technician (ET) to the service tool connector.

2. Restore electrical power to the ECM.

3. Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes. Look for the following diagnostic codes:
   • 41-3

   • 41-4

   • 100-10

   • 262-3

   • 262-4

   • 269-3

   • 269-4

   • 1785-10

   Note: Wait at least 30 seconds in order for the diagnostic codes to become active.

Expected Result:

No diagnostic codes are active.

Results:

• OK - No diagnostic code is active.

  Repair: The problem is no longer present. If the problem is intermittent, refer to Troubleshooting, "Electrical Connectors - Inspect".

  STOP

• Not OK - A 10 diagnostic code is logged at this time. The analog supply is not reaching the sensor. Proceed to Test Step 3.

• Not OK - A 262-3, 262-4, 269-3 or 269-4 diagnostic code is active at this time. There is a problem with the sensor supply for the analog sensors. Proceed to Test Step 4.

• Not OK - A 41-3 or 41-4 diagnostic code is active at this time. There is a problem with the sensor supply for the digital sensors. Proceed to Test Step 6.

Test Step 3. Check the Supply Voltage at the Sensor Connector

1. Disconnect the harness connector for the intake manifold pressure sensor and disconnect the harness connector for the oil pressure sensor.

2. Restore the electrical power to the ECM.

Note: Be sure to wiggle the harness during the following measurements in order to reveal an intermittent condition.

3. Measure the voltage between terminals A and B at the connector for each sensor.

4. Remove the electrical power from the ECM.

5. Connect all of the sensors.

Expected Result:

The voltage measurement is 5.0 ± 0.2 VDC.

Results:

• OK - The voltage measurement is 5.0 ± 0.2 VDC.

  Repair: The analog supply is reaching the sensor connectors. There may be a problem with a sensor. Perform the following procedure:

  1. Clear all diagnostic codes.

  2. Run the engine. Allow the engine to warm-up. Check if a 10 code has been logged again.
  If the code becomes active or logged, the sensor is faulty. Replace the sensor. Verify that the repair eliminates the original problem.If the code does not become active or logged, there may be an intermittent problem in the harness or in a connector. If an intermittent problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct troubleshooting procedure.

  STOP

• Not OK - The voltage measurement is not 5.0 ± 0.2 VDC. There is a problem with the harness wiring or with the ECM. Proceed to Test Step 5.

Test Step 4. Disconnect the 5 Volt Sensor(s) while you Monitor the Active Diagnostic Codes

1. Use this procedure for any 262 diagnostic codes.

   1. Monitor the active diagnostic code screen on Cat ET while you disconnect each 5 Volt sensor at the sensor connector. Check for an active 262-3 code or an active 262-4 code.

      Note: Wait at least 30 seconds in order for the diagnostic codes to become active.

   2. Disconnect the following sensors one at a time:
      • Engine oil pressure sensor

      • Fuel pressure sensor (if equipped)

      • Injection actuation pressure sensor

      • Intake manifold pressure sensor

      • Atmospheric pressure sensor

2. Use this procedure for any 269 diagnostic codes.

   1. Monitor the active diagnostic code screen on Cat ET while you disconnect each 5 Volt sensor at the sensor connector. Check for an active 269-3 code or an active 269-4 code.

      Note: Wait at least 30 seconds in order for the diagnostic codes to become active.

   2. Disconnect the following sensors one at a time:
      • L track accumulator pressure sensor

      • R track accumulator pressure sensor

      • Fuel pressure

3. Remove electrical power from the ECM.

Expected Result:

The diagnostic code deactivates when a particular sensor is disconnected.

Results:

• OK - The diagnostic code deactivates when a particular sensor is disconnected.

  Repair: Connect the suspect sensor. If the code returns, replace the sensor. Connect the connector(s). Verify that the problem is resolved.

  STOP

• Not OK - The diagnostic code remains active after the sensor(s) is disconnected. Leave the sensor(s) disconnected. The sensor(s) is not the cause of the diagnostic code. Proceed to Test Step 5.

Test Step 5. Check the 5 Volt Supply Voltages at the ECM

1. Use this procedure for any 262 diagnostic codes:

   1. Disconnect the J2/P2 ECM connector.

   2. Fabricate four jumper wires that are long enough to be used to create a test circuit at the ECM connector. Crimp connector sockets to one end of each of the jumper wires.

   3. Remove the wires from terminal locations P2-72 (5 V sensor supply) and P2-17 (sensor return). Install a jumper wire into each of these terminal locations.

   4. Remove the wires from terminal locations P2-80 (5 V sensor supply) and P2-54 (sensor return). Install a jumper wire into each of these terminal locations.

   5. Connect the J2/P2 ECM connector.

   6. Restore electrical power to the engine ECM.

   7. Measure the voltage between the jumper wire in P2-72 (5 V sensor supply) and the jumper wire in P2-17 (sensor return).

   8. Measure the voltage between the jumper wire in P2-80 (5 V sensor supply) and the jumper wire in P2-54 (sensor return).

   9. Remove electrical power from the ECM.

2. Use this procedure for any 269 diagnostic codes.

   1. Disconnect the J1/P1 ECM connector.

   2. Fabricate two jumper wires that are long enough to create a test circuit across the ECM connector. Crimp connector sockets to one end of each of the jumper wires.

   3. Remove the wires from terminal locations P1-2 (5 V sensor supply) and P1-3 (sensor return). Also remove the wire from terminal location P1-18 (sensor return). Install a jumper wire into each of these terminal locations.

   4. Connect the J1/P1 ECM connector.

   5. Restore electrical power to the engine ECM.

   6. Measure the voltage between the jumper wire in P1-2 (5 V sensor supply) and the jumper wire in P1-3 (sensor return).

   7. Measure the voltage between the jumper wire in P1-2 (5 V sensor supply) and the jumper wire in P1-18 (sensor return).

   8. Remove electrical power from the ECM.

Expected Result:

Each voltage measurement is 5.0 ± 0.2 VDC.

Results:

• OK - The voltage measurement is 5.0 ± 0.2 VDC. The ECM is operating correctly.

  Repair: The supply wire is shorted to another wire in the harness or the supply wire is shorted to engine ground. There may be an open circuit in the supply wire that is in the harness. Repair the supply wire.

  STOP

• Not OK - The voltage measurement is not 5.0 ± 0.2 VDC.

  Repair: There is a problem with the ECM. Perform the following procedure:

  1. Temporarily connect a test ECM.

     Refer to Troubleshooting, "ECM - Replace".

  2. Recheck the circuit in order to ensure that the original problem has been resolved.

     If the problem is resolved with the test ECM, install the suspect ECM. If the problem returns with the suspect ECM, replace the ECM. Verify that the problem is resolved.

     If the problem is not resolved with the test ECM, install the original ECM. There is a problem in the wiring.

  STOP

Test Step 6. Disconnect the 8 Volt Sensor while you Monitor the Active Diagnostic Codes

1. Monitor the active diagnostic code screen on Cat ET while you disconnect the coolant level sensor (if equipped) at the sensor connector. Check for an active 41-3 code or an active 41-4 code.

   Note: Wait at least 30 seconds in order for the diagnostic codes to become active.

2. Remove electrical power from the ECM.

Expected Result:

The diagnostic code deactivates when the coolant level sensor is disconnected.

Results:

• OK - The 41-3 or 41-4 diagnostic code deactivates when the coolant level sensor is disconnected.

  Repair: Connect the suspect sensor. If the code returns, replace the sensor. Connect all of the connectors. Verify that the problem is resolved.

  STOP

• Not OK - The 41-3 or 41-4 diagnostic code remains active after the coolant level sensor is disconnected. The sensor is not the cause of the diagnostic code. Leave the sensor disconnected. Proceed to Test Step 7.

Test Step 7. Check the 8 Volt Supply Voltage at the ECM

1. Disconnect the J1/P1 ECM connector.

2. Fabricate two jumper wires that are long enough to be used to create a test circuit at the ECM connectors. Crimp connector sockets to one end of each of the jumper wires.

3. Remove the wires from terminal locations P1-4 (8 V sensor supply) and P1-5 (sensor return). Install a jumper wire into each of these terminal locations.

4. Connect the J1/P1 ECM connector.

5. Restore electrical power to the engine ECM.

6. Measure the voltage between the jumper wire in P1-4 (8 V sensor supply) and P1-5 (sensor return).

7. Remove electrical power from the ECM. Restore all wires and connectors to the original configuration.

Expected Result:

The voltage measurement is 8.0 ± 0.4 VDC.

Results:

• OK - The voltage measurement is 8.0 ± 0.4 VDC. The ECM is operating correctly.

  Repair: The supply wire is shorted to another wire in the harness or the supply wire is shorted to engine ground. There may be an open circuit in the supply wire that is in the harness. Repair the supply wire.

  STOP

• Not OK - The voltage measurement is not 8.0 ± 0.4 VDC.

  Repair: There is a problem with the ECM. Perform the following procedure:

  1. Temporarily connect a test ECM.

     Refer to Troubleshooting, "ECM - Replace".

  2. Recheck the circuit in order to ensure that the original problem has been resolved.

     If the problem is resolved with the test ECM, install the suspect ECM. If the problem returns with the suspect ECM, replace the ECM. Verify that the problem is resolved.

     If the problem is not resolved with the test ECM, install the original ECM. There is a problem in the wiring.

  STOP