C1.5 and C2.2 Industrial Engines Caterpillar

This procedure covers the following codes:

Illustration 1	g03323795
Schematic for the solenoid valves

Illustration 2	g03323799
Typical view of the pin locations on the P2 connector for the solenoid valves (1) Fuel rack solenoid supply (21) Fuel rack solenoid return

Illustration 3	g03323806

Test Step 1. Inspect Electrical Connectors and Wiring

1. Thoroughly inspect the connector for the fuel rack solenoid. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.

2. Perform a 45 N (10 lb) pull test on each wire that is associated with the fuel rack solenoid.

Results:

• All connectors, pins, and sockets are correctly connected and the harness is free of corrosion, abrasion, and pinch points - Proceed to Test Step 2.

• There is a fault in the connectors and/or the harness. -

  Repair: Repair the connectors or the harness and/or replace the connectors or the harness. Ensure that all of the seals are correctly in place and ensure that the connectors are correctly connected.

  Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair eliminates the fault.

  STOP

Test Step 2. Check for Diagnostic Codes

1. Turn the keyswitch to the OFF position.

2. Connect the electronic service tool to the diagnostic connector.

3. Turn the keyswitch to the ON position.

4. Monitor the electronic service tool for active diagnostic codes and/or logged diagnostic codes.

Results:

• A 638-6 diagnostic code is active or recently logged - Proceed to Test Step 3.

• No Codes - There may be an open circuit in the circuit for the fuel rack solenoid. Proceed to Test Step 5.

Test Step 3. Disconnect the Solenoid in order to Create an Open Circuit

1. Turn the keyswitch to the OFF position.

2. Disconnect the connector for the fuel rack solenoid in order to create an open circuit.

3. Turn the keyswitch to the ON position. Check for active diagnostic codes on the electronic service tool. Wait at least 30 seconds in order for the codes to be displayed.

Results:

• The 638-6 diagnostic code is no longer active - There is a short in the solenoid.

  Repair: Perform the following procedure:

  1. Temporarily connect a replacement fuel rack solenoid to the harness.

  2. If the fault is eliminated, reconnect the suspect solenoid. If the fault returns, permanently install the replacement solenoid. Refer to Disassembly and Assembly for the correct procedure.

  STOP

• Not OK - There is still an XXXX-6 diagnostic code. Proceed to Test Step 4.

Test Step 4. Create an Open Circuit at the ECM Connector

1. Turn the keyswitch to the OFF position.

2. Disconnect the P2 connector from the ECM.

3. Turn the keyswitch to the ON position. Do not attempt to start the engine.

4. Check for active diagnostic codes on the electronic service tool. Wait at least 30 seconds in order for the codes to be displayed.

   Note: Diagnostic codes for other engine components will be active with the P2 connector disconnected. Ignore all other codes and only look for a 638-6 diagnostic code.

5. Turn the keyswitch to the OFF position.

Results:

• The 638-6 diagnostic code is no longer active with the P2 connector disconnected - The fault is in the wiring for the fuel rack solenoid.

  Repair: Replace the faulty wiring.

  Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.

  STOP

• The 638-6 diagnostic code is still active with the P2 connector disconnected -

  Repair: Perform the following repair:

  1. Make sure that the latest flash file for the application is installed in the ECM. Refer to Troubleshooting, "Flash Programming".

  2. Contact the Technical Communicator.

     Note: This consultation can greatly reduce the repair time.

  3. If the Technical Communicator recommends the use of a replacement ECM, install a replacement ECM. Refer to Troubleshooting, "Replacing the ECM".

  4. Use the electronic service tool to recheck the system for active diagnostic codes.

  5. If the fault is resolved with the replacement ECM, reconnect the suspect ECM.

  6. If the fault returns with the suspect ECM, replace the ECM.

  7. Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair eliminates the fault.

  STOP

Test Step 5. Create a Short Circuit at the Solenoid Connector

1. Turn the keyswitch to the OFF position.

2. Disconnect the connector for the fuel rack solenoid.

3. Fabricate a jumper wire. Install the wire between the two pins on the harness connector for the solenoid in order to create a short circuit.

4. Turn the keyswitch to the ON position. Check for active diagnostic codes on the electronic service tool. Wait at least 30 seconds for activation of the diagnostic codes.

5. Remove the jumper wire from the connector for the fuel rack solenoid.

Results:

• Diagnostic code 638-6 is active when the jumper wire is installed - Proceed to Test Step 6.

• Diagnostic code 638-6 is not active with the jumper installed - Proceed to Test Step 7.

Test Step 6. Check the Resistance of the Solenoid Coil

1. Turn the keyswitch to the OFF position.

2. Disconnect the connector for the fuel rack solenoid.

3. Use a suitable multimeter to measure the resistance between the two terminals on the fuel rack solenoid.

Expected Result:

The resistance of the solenoid coil should be less than 4.5 Ohms

Results:

• The measured resistance is greater than 4.5 Ohms - There is an open circuit or high resistance in the solenoid coil.

  Repair: Replace the fuel rack solenoid. Refer to Disassembly and Assembly for the correct procedure.

  Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.

  STOP

• The measured resistance is less than 4.5 Ohms - The fuel rack solenoid coil is OK

  Repair: The circuit for the fuel rack solenoid is OK. If you were directed here from another procedure, return and complete that procedure.

  STOP

Test Step 7. Check the Wiring for an Open Circuit

1. Turn the keyswitch to the OFF position.

2. Disconnect the connector for the fuel rack solenoid. Disconnect the P2 connector from the ECM.

3. Use a suitable multimeter to take the following resistance measurements:

   • P2:1 to terminal 1 on the harness connector for the fuel rack solenoid

   • P2:21 to terminal 2 on the harness connector for the fuel rack solenoid

Expected Result:

The measured resistance should be less than 2 Ohms.

Results:

• OK - Both resistance measurements are less than 2 Ohms.

  Repair: Perform the following repair:

  1. Make sure that the latest flash file for the application is installed in the ECM. Refer to Troubleshooting, "Flash Programming".

  2. Contact the Technical Communicator.

     Note: This consultation can greatly reduce the repair time.

  3. If the Technical Communicator recommends the use of a replacement ECM, install a replacement ECM. Refer to Troubleshooting, "Replacing the ECM".

  4. Use the electronic service tool to recheck the system for active diagnostic codes.

  5. If the fault is resolved with the replacement ECM, reconnect the suspect ECM.

  6. If the fault returns with the suspect ECM, replace the ECM.

  7. Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair eliminates the fault.

  STOP

• Not OK - At least one of the resistance measurements is greater than 2 Ohms. The fault is in the wiring between the fuel rack solenoid connector and the P2 connector.

  Repair: Replace the faulty wiring.

  Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.

  STOP