D250E Series II, D300E Series II, D350E Series II and D400E Series II Articulated Trucks Power Train Electronic Control System Caterpillar

Illustration 1	g00485874
Schematic Of The Center/Rear Differential Lock Solenoid Valve

This diagnostic code is recorded when the ECM reads the voltage of the solenoid circuit as being above normal.

The possible causes for this diagnostic code are listed:

• The circuit of the solenoid is shorted to +battery.

• The ECM is faulty. This is unlikely.

Note: Ensure that the CID 0970 FMI 03 for the solenoid is on-hold and that the "SERV CODE" indicator is showing "SERV CODE".

1. CHECK THE SOLENOID CIRCUIT FOR A SHORT TO +BATTERY.

   1. Turn the key start switch and the disconnect switch to the OFF position.

   2. Disconnect the machine harness from the solenoid.

   3. Disconnect the machine harness connectors J1 and J2 from the ECM.

   4. At machine harness connector J1 and J2, measure the resistance from the signal contact J2-8 (wire K745-YL) to all possible sources of +battery. The possible sources of positive voltage are connector contacts: J1-1 (wire 126-PK), J1-4 (wire A958-WH), J1-6 (wire 126-PK), J1-8 (wire 306-GN), J1-10 (wire 728-BU), J1-11 (wire 705-PK), J1-12 (703-BU), J1-17 (wire 904-BU), J1-18 (wire 704-GY), J2-1 (wire K746-PK), J2-2 (wire 368-OR), J2-7 (wire G870-GY), J2-8 (wire K745-YL), J2-13 (wire G705-GN), J2-19 (wire G704-YL) and J2-37 (wire 321-BR).

      Expected Result: The resistance should be greater than 5000 ohms for each measurement.

      Results:

      • OK - The resistance is greater than 5000 ohms. The machine harness is correct. Proceed to 2.

      • NOT OK - The resistance is NOT correct. There is a short in the machine harness. The short is between signal contact J2-8 (wire K745-YL) and the circuit with the low resistance measurement. Repair the harness or replace the harness. STOP.

2. CHECK IF THE DIAGNOSTIC CODE REMAINS.

   1. Inspect the contacts and clean the contacts of the harness connectors.

   2. Reconnect all harness connectors.

   3. Turn the disconnect switch and the key start switch to the ON position.

   4. Enter service mode of the Caterpillar Monitoring System and clear all inactive diagnostic codes.

   5. Operate the machine.

   6. Observe the status of CID 0970 FMI 03 for the solenoid.

      Expected Result: The CID 0970 FMI 03 for the solenoid is NOT present. The "SERV CODE" is NOT showing.

      Results:

      • YES - The diagnostic code is NOT present. The diagnostic code does not exist at this time. 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. STOP.

      • NO - The diagnostic code has not been corrected. It is unlikely that the ECM is faulty. Exit this procedure and perform this CID 0970 FMI 03 again. If the cause of the diagnostic code is not found, replace the ECM. See Testing And Adjusting, "Electronic Control Module (ECM) - Replace". STOP.