COLLAR 8C8172 - Caterpillar

Illustration 1 g01449764
Circuit of the Differential Axle Lock Pressure SolenoidThis diagnostic code is associated with the Differential Axle Lock Pressure Solenoid. The FMI 03 means that the ECM has determined that the voltage of the relay circuit is above normal.The possible causes of the diagnostic code are listed:
The energize circuit of the relay is shorted to the +battery circuit.
The ECM has failed. This is unlikely.Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all of the connections in the circuit are clean and secure. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear these diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code CID 2444 FMI 03 is active before performing this procedure.Note: Use a digital multimeter for the measurements in this procedure.Test Step 1. CHECK THE ENERGIZE CIRCUIT OF THE SOLENOID FOR A SHORT TO THE +BATTERY CIRCUIT.
Turn the key start switch and the disconnect switch to the ON position.
Disconnect the wires from the back of the connector at the ECM.
At the machine harness connector for the solenoid, measure the voltage from contact 1 (wire A907-BU) to frame ground. At the machine harness connector for the solenoid, measure the voltage from contact 2 (wire J809-BK) to frame ground.Expected Result:The voltage is 0 VDC.Results:
OK - There are no shorts in the wires. Proceed to Test Step 2.
NOT OK - A voltage is present in the wires. There is a short in the machine harness or in the wires. The short is to a separate voltage source.Repair: Repair the machine harness or replace the machine harness. Ensure that the fix has corrected the problem.STOPTest Step 2. CHECK THE OPERATION OF THE ECM.The disconnect switch and the key start switch remain in the OFF position. The machine harness connectors for the solenoid and the ECM remain disconnected.
Use a removal tool in order to remove the wire that energizes the solenoid from the harness. Remove wire (A907-BU) from contact J1-58 of the ECM.
Reconnect the machine harness connectors to the ECM.
Turn the disconnect switch and the key start switch to the ON position.
Observe the status of the active diagnostic code.Expected Result:The diagnostic code of FMI 03 changes to FMI 05.Results:
OK - The FMI 03 changes to a FMI 05. The FMI 05 was activated after the energize circuit for the solenoid was disconnected. The ECM has responded correctly to the condition of an open circuit in the solenoid circuit. Reconnect the disconnected wire. Wire (A907-BU) connects to the ECM at connector contact J1-58. Proceed to Test Step 3.
NOT OK - The FMI 03 does not change to a FMI 05. The diagnostic code did not change after the wire for the solenoid was disconnected.Repair: The ECM