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 current of the solenoid as being below normal.

The possible causes for this diagnostic code are listed:

• The circuit of the solenoid is open.

• The return circuit of the solenoid is open.

• The solenoid has failed.

• The ECM is faulty. This is unlikely.

Note: Ensure that the CID 0970 FMI 05 for the solenoid is on-hold and that the "SERV CODE" indicator shows "SERV CODE". This procedure can cause new diagnostic codes to be recorded. Ignore these created diagnostic codes. When the procedure is completed, clear the created diagnostic codes.

1. CHECK THE SOLENOID.

   1. Turn the disconnect switch and the key start switch to the ON position. Do not start the engine. Ensure that CID 0970 FMI 05 for the solenoid is on-hold and that the "SERV CODE" indicator is showing "SERV CODE".

   2. Disconnect the machine harness from the solenoid.

   3. At the machine harness connector for the solenoid, place a jumper wire from contact 1 (wire K745-YL) to contact 2 (wire E790-PK).

   4. Observe the status of the "SERV CODE" indicator.

      Expected Result: As the jumper wire is installed and removed, the "SERV CODE" will show and the "SERV CODE" will NOT show.

      Results:

      • YES - The circuit is correct. The solenoid is faulty. Repeat this test "CHECK THE SOLENOID" in order to verify that the solenoid has failed. Replace the solenoid. STOP.

      • NO - The diagnostic code remains. Proceed to Step 2.

2. CHECK THE HARNESS CIRCUITS FOR OPENS.

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

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

   3. At the machine harness connector for the solenoid, place a jumper wire from contact 1 (wire K745-YL) to contact 2 (wire E790-PK).

   4. At the machine harness connector J1 and J2, measure the resistance from signal contact J2-8 (wire K745-YL) to J2-3 (wire E790-PK).

      Expected Result: There should be continuity (less than 5.0 ohms resistance).

      Results:

      • OK - The machine harness is correct. Proceed to 3.

      • NOT OK - There is an open circuit in the machine harness. The open is in wire (K745-YL) or in the return wire (E790-PK) of the machine harness. Repair the harness or replace the harness. STOP.

3. 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 05 for the solenoid. The "SERV CODE" is NOT showing.

      Expected Result: The CID 0970 FMI 05 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 procedure again. If the cause of the diagnostic code is not found, replace the ECM. See Testing And Adjusting, "Electronic Control Module (ECM) - Replace". STOP.