993K Wheel Loader Vital Information Management System (VIMS) Caterpillar

Illustration 1	g01459812
Schematic of the System Voltage

This diagnostic code is recorded when the control reads the electrical system voltage that is at contact 1 as being below normal range (less than 24 volts for two seconds).

The possible causes of this diagnostic code are listed:

• A charging system component has failed.

• The wire harness has failed.

• The ECM has failed. This is unlikely.

System Response:

The outputs of the control may operate incorrectly.

Note: Make sure that the 10 Amp fuse is not open.

Test Step 1. CHECK FOR AN ACTIVE DIAGNOSTIC CODE

1. Start the engine.

2. Run the engine at high idle.

3. View the status of the diagnostic code.

Expected Result:

The diagnostic code is NOT active.

Results:

• YES - The diagnostic code is NOT active. The problem does not exist at this time. Watch for a recurrence.STOP

• NO - The diagnostic code is active. Proceed to Test Step 2.

Test Step 2. CHECK THE BATTERY VOLTAGE.

1. Measure the system voltage at the battery posts.

Expected Result:

The voltage is greater than 24 volts.

Results:

• YES - The voltage is greater than 24 DCV. Proceed to Test Step 3.

• NO - The voltage is less than 24 DCV.

  Repair: The charging system is not correct. Check the charging system. See Special Instruction, REHS0354, "Charging System Troubleshooting".

  STOP

Test Step 3. CHECK THE SYSTEM VOLTAGE AT THE ECM

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

2. Disconnect the machine harness connector from the control.

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

4. Run the engine at high idle.

5. At the machine harness connector for the ECM, measure the voltage between contact 1 and contact 2.

Expected Result:

The voltage is greater than 24 DCV.

Results:

• YES - The voltage is greater 24 DCV. This should not cause the diagnostic code.

  Repair: Inspect the connector. Connect the machine harness to the ECM. Check all connectors in the wire harness. If the CID 0168 FMI F04 remains active, replace the control. See Troubleshooting, "Electronic Control Module (ECM) - Replace".

  STOP

• NO - The voltage is less than 24 DCV. The machine harness has failed.

  Repair: Check the +battery circuit and the ground circuit in the machine harness. Repair the machine harness or replace the machine harness.

  STOP