C7.1 Industrial Engine and Generator Set Caterpillar

This procedure covers the following codes:

Also, use this procedure if the ARD fuel pump is not operating correctly.

Illustration 1	g02159018
Typical schematic of the circuit for the ARD fuel pump

Illustration 2	g02159023
Typical example of the connector for the ARD fuel pump (1) Power (2) Return

Illustration 3	g02006473
View of the pin locations on the P2 connector for the ARD fuel pump relay (41) ARD fuel pump relay return (42) ARD fuel pump relay control

The following background information is related to this procedure:

The ARD increases the exhaust gas temperature to a sufficient level in order to burn off the soot that is collected in the Diesel Particulate Filter (DPF). The ARD requires a supply of fuel and clean air. The fuel supply is provided by the ARD fuel pump.

When a regeneration is required, the ECM will activate the relay that controls the ARD fuel pump.

Override for the Relay

The electronic service tool includes the "Aftertreatment Fuel Pump Override". This override will assist the analysis of the ARD fuel pump circuit. The override can be used to control the operation of the ARD fuel pump while the engine is not running.

Test Step 1. Inspect Electrical Connectors and Wiring

1. Check that the fuses are not blown.

2. Check the harness for abrasion and pinch points from the ARD fuel pump back to the ECM. Check the harness for abrasion and pinch points from the ARD fuel pump back to the battery.

3. Inspect the terminals on the ARD fuel pump relay and then inspect the harness connector for the relay. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.

4. Inspect the connector for the ARD fuel pump. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.

5. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the ARD fuel pump.

6. Check the screw for the ECM connector for the correct torque of 6 N·m (53 lb in).

Results:

• All connectors, pins, and sockets are correctly coupled and/or inserted. The harness is free of corrosion, abrasion, and pinch points. The fuses are not blown. - Proceed to Test Step 2.

• There is a fault with the harness and connectors -

  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. Replace blown fuses.

  1. Turn the keyswitch to the ON position. Do not start the engine. Use the electronic service tool to check for active diagnostic codes.

  2. Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to activate the ARD fuel pump. Check for active diagnostic codes.

  3. Confirm that the fault has been eliminated.

     Note: If a fuse is replaced and the fault reoccurs, continue with this procedure.

  STOP

Test Step 2. Check for Active Diagnostic Codes

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

2. Turn the keyswitch to the ON position.

3. Download the following items before performing any troubleshooting or clearing any diagnostic codes:
   • Warranty Report

   • Aftertreatment Regeneration Trigger History

   • Product Status Report with Histograms

4. Start the engine.

5. Make a note of any active diagnostic codes.

6. Use the electronic service tool to select the "Aftertreatment Fuel Pump Override" in order to turn on the power for the ARD fuel pump.

7. Make a note of any active diagnostic codes.

Results:

• Diagnostic code 5423-5 is active when the ARD fuel pump is switched off. - Proceed to Test step 3.

• Diagnostic code 5423-6 is active when the ARD fuel pump is switched on. - Proceed to Test Step 5.

• An active diagnostic code or a recently logged diagnostic code was not displayed. - There may be a fault with the switched power circuit for the ARD fuel pump. The ECM does not monitor the status of this condition. Proceed to Test Step 9.

Test Step 3. Create a Short Circuit at the ARD Fuel Pump Relay

1. Turn the keyswitch to the OFF position.

2. Disconnect the connector for the ARD fuel pump relay.

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

4. Use the jumper wire to connect Test Point 1 to Test point 2 on the harness connector for the ARD fuel pump relay. Refer to Illustration 1.

5. Start the engine. Use the electronic service tool to check for an active 5423-5 diagnostic code.

6. Use the electronic service tool to select the "Aftertreatment Fuel Pump Override" in order to activate the ARD fuel pump. Check for an active 5423-6 diagnostic code.

7. Stop the engine.

8. Remove the jumper.

Results:

• A 5423-6 diagnostic code was active with the jumper installed. -

  Repair: Perform the following repair:

  1. Install a replacement relay.

  2. Reconnect the connector for the ARD fuel pump relay.

  3. Start the engine. Use the electronic service tool to check for an active 5423-5 diagnostic code.

  4. Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to activate the ARD fuel pump. Check for an active 5423-6 diagnostic code.

  5. Confirm that the fault has been eliminated.

  STOP

• A 5423-5 diagnostic code is still active with the jumper installed. - Reconnect the ARD fuel pump relay and proceed to Test Step 4.

Test Step 4. Create a Short Circuit at the 31-Pin Connector

1. Turn the keyswitch to the OFF position.

2. Disconnect the 31-pin connector.

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

4. Insert one end of the jumper into socket 19 on the 31-pin connector on the engine harness. Insert the other end of the jumper into socket 26 on the 31-pin connector on the engine harness.

5. Start the engine. Use the electronic service tool to check for a 5423-5 diagnostic code.

   Note: While the 31-pin connector is disconnected, diagnostic codes for the other components that are connected to the 31-pin connector will be active. Disregard the diagnostic codes for all the other components. Only address the 5423 diagnostic codes.

6. Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to activate the ARD fuel pump. Check for an active 5423-6 diagnostic code.

   Note: While the 31-pin connector is disconnected, diagnostic codes for the other components that are connected to the 31-pin connector will be active. Disregard the diagnostic codes for all the other components. Only address the 5423 diagnostic codes.

7. Stop the engine.

8. Remove the jumper.

Results:

• A 5423-6 diagnostic code is active with the jumper installed. - The fault is in the wiring between the 31-pin connector and the ARD fuel pump relay.

  Repair: Perform the following repair:

  1. Repair the faulty wiring or replace the faulty wiring.

  2. Reconnect the 31-pin connector. Use the electronic service tool to clear all logged diagnostic codes.

  3. Start the engine. Use the electronic service tool to check for an active 5423-5 diagnostic code.

  4. Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to activate the ARD fuel pump. Check for an active 5423-6 diagnostic code.

  5. Confirm that the fault has been eliminated.

  STOP

• A 5423-5 diagnostic code is still active with the jumper installed. - Proceed to Test Step 7.

Test Step 5. Create an Open Circuit at the Relay

1. Turn the keyswitch to the OFF position.

2. Disconnect the ARD fuel pump relay connector.

3. Start the engine. Use the electronic service tool to check for an active 5423-5 diagnostic code.

4. Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to activate the ARD fuel pump. Check for an active 5423-6 diagnostic code.

Results:

• A 5423-6 diagnostic code is still active with the ARD fuel pump relay disconnected. - The ARD fuel pump relay is OK. Proceed to Test Step 6.

• A 5423-5 diagnostic code became active with the ARD fuel pump relay disconnected. - The wiring for the ARD fuel pump relay is OK.

  Repair: Perform the following repair:

  1. Stop the engine.

  2. Install a replacement relay.

  3. Reconnect the connector for the ARD fuel pump.

  4. Start the engine. Use the electronic service tool to check for an active 5423-5 diagnostic code.

  5. Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to activate the ARD fuel pump. Check for an active 5423-6 diagnostic code.

  6. Confirm that the fault has been eliminated.

  STOP

Test Step 6. Create an Open Circuit at the 31-Pin Connector

1. Turn the keyswitch to the OFF position.

2. Disconnect the 31-pin connector.

3. Start the engine. Use the electronic service tool to check for an active 5423-5 diagnostic code.

   Note: While the 31-pin connector is disconnected, diagnostic codes for the other components that are connected to the 31-pin connector will be active. Disregard the diagnostic codes for all the other components. Only address the 5423 diagnostic codes.

4. Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to activate the ARD fuel pump. Check for an active 5423-6 diagnostic code.

   Note: While the 31-pin connector is disconnected, diagnostic codes for the other components that are connected to the 31-pin connector will be active. Disregard the diagnostic codes for all the other components. Only address the 5423 diagnostic codes.

5. Stop the engine.

Results:

• A 5423-5 diagnostic code is active with the 31-pin connector disconnected. - The fault is in the wiring between the 31-pin connector and the ARD fuel pump relay.

  Repair: Perform the following repair:

  1. Repair the faulty wiring or replace the faulty wiring.

  2. Reconnect the 31-pin connector. Use the electronic service tool to clear all logged diagnostic codes.

  3. Start the engine. Use the electronic service tool to check for an active 5423-5 diagnostic code.

  4. Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to activate the ARD fuel pump. Check for an active 5423-6 diagnostic code.

  5. Confirm that the fault has been eliminated.

  STOP

• A 5423-6 diagnostic code is still active with the jumper installed. - Proceed to Test Step 7.

Test Step 7. Bypass the Engine Harness

1. Turn the keyswitch to the OFF position.

2. Disconnect the P2 connector.

3. Inspect the P2/J2 connector. Refer to Troubleshooting, "Electrical Connectors - Inspect"

4. Remove the wires from P2:41 and P2:42.

5. Remove the wires from socket 26 and socket 19 on the 31-pin connector on the engine harness.

6. Fabricate two jumper wires that are long enough to reach from the ECM to the 31-pin connector.

7. Insert one end of a jumper into P2:41. Insert the other end of the jumper into socket 19 on the 31-pin connector on the engine harness.

8. Insert one end of the other jumper into P2:42. Insert the other end of the jumper into socket 26 on the 31-pin connector on the engine harness.

9. Reconnect the P2 connector. Reconnect the 31-pin connector.

10. Start the engine. Use the electronic service tool to check for an active 5423-5 diagnostic code.

11. Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to activate the ARD fuel pump. Check for an active 5423-6 diagnostic code.

12. Stop the engine.

13. Disconnect the P2/J2 connector. Disconnect the 31-pin connector.

14. Remove the jumper wire.

Results:

• OK - There are no active 5423 diagnostic codes at this time. The fault is in the engine harness between the ECM and the 31-pin connector.

  Repair: Perform the following repair:

  1. Repair the faulty wiring or replace the faulty wiring.

  2. Reconnect the P2/J2 connector. Reconnect the 31-pin connector.

  3. Start the engine. Use the electronic service tool to check for an active 5423-5 diagnostic code.

  4. Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to activate the ARD fuel pump. Check for an active 5423-6 diagnostic code.

  5. Confirm that the fault has been eliminated.

  STOP

• Not OK - A 5423 diagnostic code is still active at this time. Return all wires to the original configuration and proceed to Test Step 8.

Test Step 8. Check the ECM

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 test ECM, install a test ECM. Refer to Troubleshooting, "Replacing the ECM".

4. Use the electronic service tool in order to clear all logged diagnostic codes.

5. Start the engine.

6. Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to activate the ARD fuel pump. Check for active diagnostic codes.

7. Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to deactivate the ARD fuel pump. Check for active diagnostic codes.

Results:

• There are no active 5423 diagnostic codes - The replacement ECM functions correctly.

  Repair: Perform the following procedure:

  1. Reconnect the suspect ECM.

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

  3. 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 - The fault is still present with the replacement ECM. Do not use the replacement ECM.

  Repair: Repeat this test procedure from Test Step 1.

  STOP

Test Step 9. Check the Input Voltage to the Relay

1. Disconnect the connector for the ARD fuel pump relay.

2. Use a voltmeter to check the voltage between Test Point A on the harness connector for the ARD fuel pump relay and a suitable ground.

Expected Result:

For 12 V systems, the measured voltage should be a constant 11.0 to 13.5 VDC.

For 24 V systems, the measured voltage should be a constant 22.0 to 27.0 VDC.

Results:

• OK - The voltage is within the expected range. The wiring between the battery and the ARD fuel pump relay is OK. Reconnect the connector for the relay and proceed to Test Step 10.

• Not OK - The voltage is not within the expected range. The fault is in the wiring between the battery and the ARD fuel pump.

  Repair: Perform the following repair:

  1. Replace any blown fuses.

  2. Repair the faulty wiring or replace the faulty wiring.

  3. Start the engine.

  4. Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to activate the ARD fuel pump.

  5. Confirm that the fault has been eliminated.

  6. Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to deactivate the ARD fuel pump

  STOP

Test Step 10. Check the Voltage at the Connector for the ARD Fuel Pump

1. Disconnect the connector for the ARD fuel pump.

2. Start the engine.

3. Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to activate the ARD fuel pump.

4. Measure the voltage at terminal 1 of the harness connector for the ARD fuel pump to a suitable ground.

Expected Result:

For 12 V systems, the measured voltage should be a constant 11.0 to 13.5 VDC.

For 24 V systems, the measured voltage should be a constant 22.0 to 27.0 VDC.

Results:

• OK - The ARD fuel pump is receiving the correct voltage. Proceed to Test Step 11.

• Not OK - The ARD fuel pump is not receiving the correct voltage. Proceed to Test Step 12.

Test Step 11. Check the Return Wire for the ARD Fuel Pump

1. Start the engine.

2. Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to activate the ARD fuel pump.

3. Measure the voltage from terminal 1 to terminal 2 of the harness connector for the ARD fuel pump.

Expected Result:

For 12 V systems, the measured voltage should be a constant 11.0 to 13.5 VDC.

For 24 V systems, the measured voltage should be a constant 22.0 to 27.0 VDC.

Results:

• OK - The wiring between the ARD fuel pump and the negative terminal on the battery is OK.

  Repair: Perform the following repair:

  1. Replace the ARD fuel pump. Refer to Disassembly and Assembly, "Fuel Pump (ARD) - Remove and Install".

  2. Start the engine.

  3. Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to activate the ARD fuel pump.

  4. Confirm that the fault has been eliminated.

  STOP

• Not OK - The fault is in the wiring between the ARD fuel pump and the negative terminal on the battery.

  Repair: Repair the faulty wiring or replace the faulty wiring.Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to activate the ARD fuel pump and confirm that the repair eliminates the fault.

  STOP

Test Step 12. Bypass the Relay

1. Stop the engine.

2. Disconnect the connector for the ARD fuel pump relay.

3. Ensure that the connector for the ARD fuel pump is disconnected.

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

5. Use the jumper wire to connect Test Point (A) to Test point (B) on the harness connector for the ARD fuel pump relay. Refer to Illustration 1.

6. Measure the voltage from terminal 1 on the harness connector for the ARD fuel pump to a suitable ground.

7. Remove the jumper.

Expected Result:

For 12 V systems, the measured voltage should be a constant 11.0 to 13.5 VDC.

For 24 V systems, the measured voltage should be a constant 22.0 to 27.0 VDC.

Results:

• OK - The voltage is within the expected range. There may be a fault with the relay.

  Repair: Perform the following repair:

  1. Install a replacement relay.

  2. Start the engine.

  3. Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to activate the ARD fuel pump.

  4. Confirm that the fault has been eliminated.

  STOP

• Not OK - The voltage is not within the expected range. The fault is in the wiring between the ARD fuel pump and the ARD fuel pump relay.

  Repair: Repair the faulty wiring or replace the faulty wiring.Start the engine. Use the "Aftertreatment Fuel Pump Override" in the electronic service tool to activate the ARD fuel pump and confirm that the repair eliminates the fault.

  STOP