980G Wheel Loader, 824G Wheel Dozer, 825G Soil Compactor and 826G Landfill Compactor Implement Electronic Control System Caterpillar

Illustration 1	g00716026
Schematic for the Engine Fan Reversing Solenoid

This diagnostic code is recorded when the ECM detects a short to ground in the electrical path from the ECM to the solenoid.

The possible causes for this diagnostic code are listed:

• The internal windings for the solenoid have low impedance.

• The internal windings for the solenoid are shorted.

• The signal circuit from the ECM to the solenoid is shorted to ground.

System Response:

The machine response is listed:

• The engine cooling fan will not operate in the reverse direction.

Note: All solenoid return lines connect to contacts J1-7 and J2-3 (wire H716-WH) of the implement ECM.

Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code is corrected.

Note: Ensure that the diagnostic code indicator is active and that the diagnostic code is active.

Test Step 1. CHECK THE SOLENOID.

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

2. Observe the ON/OFF status of the diagnostic code indicator.

3. Disconnect the solenoid with the diagnostic code from the harness.

Expected Result:

The diagnostic code indicator remains active.

Results:

• YES - The diagnostic code indicator remains active and the diagnostic code remains active. The harness has failed or the ECM has failed. Proceed to test step 2.

• NO - The diagnostic code indicator is inactive.

  Repair: The solenoid valve has failed or the connecting harness has failed. Repeat this test in order to verify the failure. Repair the solenoid or replace the solenoid. Repair the connecting harness or replace the connecting harness at the solenoid.

  Stop.

Test Step 2. CHECK FOR A SHORTED HARNESS.

1. Turn the disconnect switch to the OFF position.

2. The solenoid valve from the previous test step remains disconnected.

3. Disconnect the harness from the implement ECM.

4. At the harness connector for the ECM, measure the resistance between contact for the failed solenoid circuit J2-19 (wire H704-PK) and contact J1-2 (ground) (wire A272-BK).

Expected Result:

The resistance is less than 5000 Ohms.

Results:

• YES - Resistance is less than 5000 Ohms (continuity).

  Repair: The harness has failed. The corresponding solenoid wire is shorted to ground in the harness. Repair the harness or replace the harness.

  Stop.

• NO - Resistance is greater than 5000 Ohms (no continuity).

  Repair: The harness circuit resistance is correct. It is unlikely that the ECM has failed. Exit this procedure and perform this troubleshooting procedure again. Also recheck if the diagnostic code indicator is active for this diagnostic code. If the cause is not found, replace the ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  Stop.