988G Wheel Loader Power Train Caterpillar

Illustration 1	g00592670
Schematic of the Solenoid Valve (Fan Reversing)

This diagnostic code is associated with the Solenoid Valve (Fan Reversing). The FMI 05 means that the ECM has determined that the current of the solenoid is below normal.

The possible causes of this diagnostic code are listed below:

• 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.

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 of CID 0485 FMI 05 is active before performing this procedure.

Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.

System Response:

When this diagnostic code occurs, the direction of the engine fan will not reverse.

Test Step 1. CHECK THE SOLENOID.

1. Turn the disconnect switch and the key start switch to the ON position. Do not start the engine.

2. Disconnect the solenoid with the active diagnostic code from the machine harness.

3. At the machine harness connector for the solenoid, place a jumper wire from contact 1 (wire H704-PK) to contact 2 (wire 200-BK).

4. Observe the status of the CID 0485 FMI 05.

Expected Result:

The CID 0485 FMI 05 remains active. The FMI has not changed and the "05" is still active.

Results:

• YES - The diagnostic code remains active. The jumper wire does not affect the diagnostic code. Proceed to Test Step 2.

• NO - The diagnostic is no longer active. The solenoid has failed.

  Repair: The solenoid has failed. Repeat this Test Step "CHECK THE SOLENOID" in order to verify the solenoid failure. Replace the solenoid. Verify that the new solenoid corrects the problem.

  Stop.

Test Step 2. CHECK THE HARNESS FOR AN OPEN.

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

2. Disconnect the machine harness connector(s) from the ECM.

3. The jumper wire that was installed in the previous Test Step remains in place.

4. At the machine harness connector, measure the resistance from signal contact J1-10 (wire H704-PK) to contact J1-2 (wire 200-BK).

Expected Result:

The resistance is less than 5.0 ohms.

Results:

• OK - The resistance is less than 5.0 ohms. The machine harness is correct. Proceed to Test Step 3.

• NOT OK - The resistance is greater than 5000 ohms. The resistance measurement is not correct. There is an open circuit in the machine harness.

  Repair: The open is in wire H704-PK or in wire 200-BK of the machine harness. Repair the machine harness or replace the machine harness.

  Stop.

Test Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS.

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

2. Reconnect all harness connectors.

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

4. Operate the machine.

5. Check the status of the CID 0485 FMI 05.

Expected Result:

The CID 0485 FMI 05 is active.

Results:

• YES - The CID 0485 FMI 05 is active. The diagnostic code has not been corrected. The ECM may have failed.

  Repair: It is unlikely that the ECM has failed. 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.

• NO - The CID 0485 FMI 05 is not active. The diagnostic code 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.

  Stop.