824H Wheel Dozer, 825H Soil Compactor and 826H Landfill Compactor Electrohydraulic System Caterpillar

Illustration 1	g01157905
Schematic of the ECM +battery supply

This diagnostic code is recorded when the ECM detects that +battery voltage at contact J1-40 is below normal or is not present.

The possible causes for this diagnostic code are listed:

• The + battery circuit for contact J1-40 between the fuse and the ECM is open or has a bad connection.

• The ECM is faulty. This is unlikely.

Note: In order for the ECM to activate this diagnostic code. the ECM must be receiving +battery power at the other +battery contacts, J1-1 and J1-6. Accordingly, this procedure looks for an open or bad connection between contact J1-40 and the implement fuse.

System Response:

The machine response is listed:

• All implement functions will be disabled.

• The pilot on/off solenoid valve will be disabled.

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

Test Step 1. CHECK THE HARNESS

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

2. Disconnect connector J1 from the implement ECM.

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

4. Measure the voltage on the harness side of connector between J1-40 and the machine ground.

Expected Result:

The voltage measures +battery voltage.

Results:

• YES - The voltage measures battery voltage. Proceed to Test Step 2.

• NO - The voltage measures less than battery voltage.

  Repair: There is either an open or a bad connection in the machine wiring harness between the implement fuse and the ECM. Refer to the machine electrical schematic for your machine. Examine all connections in the +battery circuit for contact J1-40. Ensure that all pins and sockets in the connectors are clean and tight. Repair the harness or replace the harness.

  Stop.

Test Step 2. CHECK THE STATUS OF THE DIAGNOSTIC CODE

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

2. Reconnect all machine harness connectors that have been disconnected.

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

4. Check the status of the CID 1393 FMI 04 diagnostic code.

Expected Result:

The CID 1393 FMI 04 diagnostic code is no longer active.

Results:

• YES - The CID 1393 FMI 04 diagnostic code is no longer active.

  Repair: The diagnostic code no longer exists. The initial diagnostic code was probably caused by a poor electrical connection at one of the harness connectors that was disconnected and reconnected. Resume normal machine operation.

  Stop.

• NO - The diagnostic code is still active.

  Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. Refer to the full machine electrical system schematic. Ensure that all connections in the solenoid circuit are intact, clean and secure. Check the circuit for broken wiring. If the cause of this diagnostic code is not found in the machine harness, replace the ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  Stop.