SUPPORT ASSEM. 8A2756 - Caterpillar

inch) long.
Install the wire between pin 21 and pin 22 on the 40-pin connector on the harness between the engine and the CEM.
Turn the keyswitch to the ON position. Wait for 10 seconds. Check for active diagnostic codes on the electronic service tool.Note: While the 40-pin connector is disconnected, diagnostic codes for the other components that are connected to the 40-pin connector will be active. Disregard the diagnostic codes for all the other components. Only address the 3479 diagnostic codes.
Remove the jumper wire.Results:
A 3479-5 diagnostic code was active before installing the jumper. A 3479-6 diagnostic code is active when the jumper is installed - The fault is in the CEM harness.Repair: Repair the faulty wiring or replace the faulty wiring.Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.STOP
A 3479-5 diagnostic code is still active with the jumper installed. - Reconnect the 40-pin connector. Proceed to Test Step 5.Test Step 5. Create a Short Circuit at the 31-Pin Connector
Turn the keyswitch to the OFF position.
Disconnect the 31-pin connector.
Fabricate a jumper wire that is 150 mm (6 inch) long.
Install the wire between pin 21 and pin 22 on the 31-pin connector on the harness between the engine and the CEM.
Turn the keyswitch to the ON position. Wait for 10 seconds. Check for active diagnostic codes on the electronic service tool.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 3479 diagnostic codes.
Remove the jumper wire.Results:
A 3479-5 diagnostic code was active before installing the jumper. A 3479-6 diagnostic code is active when the jumper is installed - The fault is in the harness between the 31-pin connector and the 40-pin connector.Repair: Repair the faulty wiring or replace the faulty wiring.Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.STOP
A 3479-5 diagnostic code is still active with the jumper installed. - Proceed to Test Step 9.Test Step 6. Create an Open Circuit at the Solenoid
Turn the keyswitch to the OFF position.
Disconnect the connector for the suspect solenoid valve.
Turn the keyswitch to the ON position. Wait for 10 seconds. Check for active diagnostic codes on the electronic service tool.Results:
An XXXX-6 diagnostic code was active before disconnecting the valve. An XXXX-5 diagnostic code is active with the valve disconnected. - Repair: Perform the following procedure:
Temporarily connect a replacement for the suspect valve to the harness.
Turn the keyswitch to the ON position. Use the electronic service tool in order to check for active diagnostic codes. Wait at least 30 seconds in order for the codes to be displayed.
If the fault is eliminated, reconnect the suspect valve. If the fault returns, permanently install the replacement valve. Refer to Disassembly and Assembly for the correct procedure.STOP
A 3479-6 diagnostic code is still active with the valve disconnected. - Reconnect the ARD pilot fuel