DIFFERENTIAL GP 2738991 - Caterpillar

Illustration 1 g01667449
Schematic for the Differential Lock SolenoidThis diagnostic code is associated with the Differential Lock Solenoid. The FMI 05 means that the Chassis ECM has detected that the current for the solenoid circuit is below normal.Conditions that could cause this diagnostic code to be activated are:
The energize circuit of the solenoid is open.
The return circuit of the solenoid is open.
The solenoid has failed.
The ECM has failed. This is unlikely. System Response:When this diagnostic code is active, a Level 1 Warning will occur.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.Note: The resistance of the solenoid coil should be 27 1.4 ohms at 20 °C (68.0 °F).Test Step 1. CHECK THE STATUS OF THE DIAGNOSTIC CODE
Turn the disconnect switch and the key start switch to the OFF position.
Inspect the harness connectors. Clean the contacts of the harness connectors and check the wires for damage to the insulation that is caused by excessive heat, corrosion, or chafing.
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit.
Use the Caterpillar Electronic Technician (ET) service tool, if available, in order to perform a "Wiggle Test" on the machine wiring harness. The wiggle test can detect intermittent shorts or opens in the machine wiring harness.
Reconnect all harness connectors. Make sure that the connectors are fully seated and the clips for each connector are completely fastened.
Turn the disconnect switch and the key start switch to the ON position.
Operate the machine.
Determine if the CID 0740 FMI 05 diagnostic code is still active.Expected Result:The CID CID 0740 FMI 05 diagnostic code is still active.Results:
YES - The CID 0740 FMI 05 diagnostic code remains active. Proceed to Test Step 2.
NO - The CID 0740 FMI 03 code is not active. The problem does not exist at this time.Repair: The initial diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connectors that was disconnected and reconnected. Resume normal machine operation.STOPTest Step 2. CHECK THE SOLENOID
Disconnect the machine harness from the solenoid.
At the machine harness connector for the solenoid, place a jumper wire from contact 1 (wire A975-BU) to contact 2 (wire H808-WH).
The disconnect switch and the key start switch remain in the ON position. Do not start the engine.
Observe the status of the CID 0740 FMI 05 diagnostic code.Expected Result:The CID 0740 FMI 05 diagnostic code is no longer active. A CID 0740 FMI 06 diagnostic code becomes active when the jumper wire is connected.Results:
YES - The CID 0740 FMI 05 diagnostic code is no longer active. A CID 0740 FMI 06 diagnostic code becomes active when the jumper wire is connected. The solenoid may have failed.Repair: Temporarily connect a known good sensor. Check for active diagnostic codes. Allow 15 seconds for any codes to activate. If the new sensor fixes the problem, reconnect the suspect sensor. If the problem returns,