HOUSING AS 8G8919 - Caterpillar

Illustration 1 g01371111
Schematic of the retarder solenoid on the CX31
This diagnostic trouble code is associated with the retarder solenoid. The FMI 5 means that the ECU has determined that an open in the circuit exists.The possible causes of this diagnostic trouble code are listed below:
The energize circuit of the solenoid is open.
The return circuit of the solenoid is open.
The solenoid has failed.
The ECU has failed. This is unlikely. Note: The following test procedure may create other diagnostic trouble codes. Ignore these created diagnostic trouble codes and clear these diagnostic trouble codes when the original diagnostic trouble code has been corrected. Ensure that the diagnostic trouble code of SPN 744 FMI 5 is active before performing this procedure.Note: Use a digital multimeter for the measurements in this procedure.Test Step 1. CHECK THE SOLENOID
Turn the disconnect switch and the key start switch to the ON position. Do not start the engine.
Disconnect the solenoid with the active diagnostic code from the machine harness.
At the machine harness connector for the solenoid, place a jumper wire from contact 1 (wire K744-BU(Blue)) to contact 2 (wire 921-WH(White)).
Observe the status of the diagnostic code. Expected Result:The diagnostic code is active. Then, the diagnostic code changes from FMI 5 to FMI 6 as the jumper wire is installed.Results:
YES - The diagnostic code remains active. The jumper wire does not affect the diagnostic code. Proceed to Test Step 2.
NO - The diagnostic is no longer active. The solenoid has failed.Repair: The solenoid has failed. Replace the solenoid. Verify that the new solenoid corrects the problem.STOPTest Step 2. CHECK THE HARNESS FOR AN OPEN
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness connectors from the ECU.
The jumper wire that was installed in the previous Test Step remains in place.
At the machine harness connector, measure the resistance from signal contact J1-65 to contact J1-60. Expected Result:The resistance is less than 5.0 ohms.Results:
OK - The resistance is less than 5.0 ohms. The machine harness is correct. Proceed to Test Step 3.
NOT OK - The resistance is greater than 5000 ohms. The resistance measurement is not correct. There is an open circuit in the machine harness.Repair: Repair the machine harness or replace the machine harness.STOPTest Step 3. CHECK THE OPERATION OF THE ECU.The disconnect switch and the key start switch remain in the OFF position. The harness connector for the solenoid and the connectors for the ECU remain disconnected.
Remove the jumper wire that was installed in the last test step.
At the J2 connector for the ECU, use a wire removal tool to remove wire K744-BU(Blue) from contact J1-65.
Reconnect the machine harness connectors to the ECU.
Turn the disconnect switch and the key start switch to the ON position.
Use a multimeter probe that is not connected to a multimeter or a similar device to make contact with the ECU at contact J1-65 through the empty space in the J1 connector.
Observe the status of the diagnostic code. Ground the other end of the multimeter probe to frame ground.