C1.5 and C2.2 Industrial Engines Caterpillar

This procedure covers the following codes:

The position sensor is an integral part of the fuel rack solenoid. If the following procedure indicates a fault with the position sensor, then the entire solenoid must be replaced.

The following background information is related to this procedure:

The ECM supplies 5 VDC to terminal "B" of the fuel rack solenoid position sensor connector. The sensor common from the ECM connector goes to terminal "A" of the fuel rack solenoid position sensor connector. The sensor supply is output short circuit protected. A short circuit to the battery will not damage the circuit inside the ECM. The signal voltage from terminal "C" of the fuel rack solenoid position sensor connector is supplied to P2:49 on the ECM connector.

Illustration 1	g03330725
Schematic for the fuel rack position sensor

Illustration 2	g03330798
Typical view of the pin locations on the P2 connector for the position sensors (48) Fuel rack solenoid position sensor ground (49) Fuel rack solenoid position sensor 5 VDC supply (50) Fuel rack solenoid position sensor signal

Illustration 3	g03330886
View of the harness connector for the fuel rack solenoid position sensor (A) Fuel rack position sensor ground (B) Fuel rack position sensor 5 VDC supply (C) Fuel rack solenoid position sensor signal

Test Step 1. Verify All Active and Recently Logged Diagnostic Codes

1. Turn the keyswitch to the ON position. Wait at least 10 seconds for activation of the diagnostic codes.

2. Verify if any of the diagnostic codes that are listed in Table 1 are active or recently logged.

Results:

• One or more of the preceding diagnostic codes are active or recently logged. - Proceed to Test Step 2.

• None of the preceding diagnostic codes are active or recently logged. -

  Repair: The fault may be intermittent. Refer to Troubleshooting, "Electrical Connectors - Inspect" in order to identify intermittent faults.

  STOP

Test Step 2. Inspect Electrical Connectors And Wiring

1. Thoroughly inspect the terminal connections on the P2/J2 ECM connectors.

2. Thoroughly inspect the connector for the fuel rack solenoid position sensor.

3. Refer to Troubleshooting, "Electrical Connectors - Inspect".

4. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the fuel rack solenoid position sensor.

5. Check the harness for abrasions and for pinch points from the fuel rack solenoid position sensor back to the ECM.

Expected Result:

All connectors, pins, and sockets are correctly connected. The harness should be free of corrosion, abrasions, and pinch points.

Results:

• OK - Proceed to Test Step 3.

• Not OK -

  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 3. Measure the Supply Voltage at the Sensor Connector

1. Turn the keyswitch to the OFF position.

2. Disconnect the fuel rack solenoid position sensor from the harness.

3. Turn the keyswitch to the ON position.

4. Measure the voltage between terminal A and terminal B on the harness connector for the sensor.

5. Reconnect the sensor to the harness.

Expected Result:

The measured voltage is 4.9 to 5.1 VDC.

Results:

• OK - The sensor supply voltage is correct. Proceed to Test Step 5.

• The sensor supply voltage is out of the nominal range. - Proceed to Test Step 4.

Test Step 4. Measure the Supply Voltage at the ECM

1. Turn the keyswitch to the OFF position.

2. Disconnect the P2 connector from the ECM.

3. Turn the keyswitch to the ON position.

4. Use a suitable multimeter to measure the voltage between J2:48 and J2:50

5. Turn the keyswitch to the OFF position.

6. Reconnect the P2 connector.

Expected Result:

The voltage measures 4.9 to 5.1 VDC.

Results:

• OK - The voltage is within the expected range. The fault is in the 5 VDC supply wire or the ground wire between the sensor 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

• Not OK - The voltage is not within the expected range.

  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 at a Caterpillar dealer.

     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. Verify the Type of Active Diagnostic Code

1. Turn the keyswitch to the ON position. Wait at least 10 seconds for activation of the diagnostic codes.

2. Use the electronic service tool to check for active diagnostic codes. Record all active diagnostic codes.

Expected Result:

One of the diagnostic codes that are listed in Table 1 is active.

Results:

• Short Circuit - A 733-4 diagnostic code is active at this time. Proceed to Test Step 6.

• Open Circuit or short to ground - A 733-3 diagnostic code is active at this time. Proceed to Test Step 8.

• A short circuit diagnostic code is not active. An open circuit diagnostic code is not active - An intermittent fault may exist.

  Repair: Refer to Troubleshooting, "Electrical Connectors - Inspect" in order to identify intermittent faults.

  STOP

Test Step 6. Create an Open Circuit at the Sensor Connector

1. Turn the keyswitch to the OFF position.

2. Disconnect the fuel rack solenoid position sensor connector.

3. Turn the keyswitch to the ON position. Wait for at least 10 seconds for activation of the diagnostic codes.

4. Use the electronic service tool to check the "Active Diagnostic Code" screen. Check for a 733-3 diagnostic code.

5. Turn the keyswitch to the OFF position.

Expected Result:

A 733-3 diagnostic code is now active.

Results:

• A 733-4 diagnostic code was active before disconnecting the sensor. A 733-3 diagnostic code is active with the sensor disconnected. -

  Repair: Perform the following repair:

  1. Reconnect the connector for the sensor.

  2. Turn the keyswitch to the ON position. Use the electronic service tool to check for active diagnostic codes.

  3. If the 733-4 diagnostic code returns, there is a short in the sensor.

  4. Install a replacement fuel rack solenoid. Refer to Disassembly and Assembly, "Position Sensor (Governor Control) - Remove and Install" for the correct procedure.

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

  STOP

• The 733-4 diagnostic code remains active with the sensor disconnected. - The sensor is OK. Reconnect the sensor. Proceed to Test Step 7.

Test Step 7. Create an Open Circuit at the ECM Connector

1. Turn the keyswitch to the OFF position.

2. Disconnect the P2 connector from the ECM.

   Thoroughly inspect the P2/J2 connectors for corrosion and/or damaged seals.

3. Turn the keyswitch to the ON position. Wait at least 10 seconds for activation of the diagnostic codes.

4. Use the electronic service tool in order to monitor the "Active Diagnostic Code" screen. Check for a 733-3 diagnostic code.

   Note: Diagnostic codes for all of the engine sensors will be active with the P2 connector disconnected. Ignore all other codes and only look for a 733-X diagnostic code.

Results:

• A 733-4 diagnostic code was active before disconnecting the P2 connector. A 733-3 diagnostic code is active with the P2 connector disconnected. - The fault is in the wiring for the suspect sensor between the sensor connector and the P2 connector.

  Repair: Perform the following repair:

  1. Replace the faulty wiring.

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

  STOP

• The 733-4 diagnostic code is still active with the P2 connector disconnected. - The wiring is OK.

  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 at a Caterpillar dealer.

     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 8. Create a Short Circuit at the Sensor Connector

1. Turn the keyswitch to the OFF position.

2. Disconnect the fuel rack solenoid position sensor connector.

3. Fabricate a jumper wire that is 150 mm (6 inch) long.

4. Install the jumper wire between terminal A and terminal C on the harness connector for the sensor.

5. Turn the keyswitch to the ON position. Wait at least 10 seconds for activation of the diagnostic codes.

6. Access the "Active Diagnostic Codes" screen on the electronic service tool and check for an active 733-4 diagnostic code.

7. Remove the jumper.

Results:

• A 733-3 diagnostic code was active before the jumper was installed. A 733-4 diagnostic code is active when the jumper is installed. -

  Repair: Perform the following repair:

  1. Reconnect the connector for the sensor.

  2. Turn the keyswitch to the ON position. Use the electronic service tool to check for active diagnostic codes.

  3. If the 733-3 diagnostic code returns, there is an open circuit in the sensor.

  4. Install a replacement sensor. Refer to Disassembly and Assembly, "Position Sensor (Governor Control) - Remove and Install" for the correct procedure.

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

  STOP

• The 733-3 diagnostic code remains active when the jumper is installed. - The sensor is OK. Proceed to Test Step 9.

Test Step 9. Check the Sensor Signal Wire for an Open Circuit

1. Turn the keyswitch to the OFF position.

2. Disconnect the fuel rack solenoid position sensor connector.

3. Disconnect the P2 connector from the ECM.

   Thoroughly inspect the P2/J2 connectors for corrosion and/or damaged seals. Repair if necessary.

4. Use a suitable multimeter to measure the resistance between terminal C on the harness connector for the sensor and P2:49.

Results:

• The measured resistance is greater than 2 Ohms - The fault is in the signal wire between the sensor 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

• The measured resistance is less than 2 Ohms - The wiring is OK.

  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 at a Caterpillar dealer.

     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