This diagnostic code is recorded when the power system voltage for the ECM is greater than 16 DCV. The solenoids may be damaged if the voltage remains high for an extended period of time.
The possible causes of this diagnostic code are listed below:
- A charging system component has failed.
- The ECM may have failed. This is unlikely.
Note: Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure and in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.
Test Step 1. CHECK THE CHARGING SYSTEM.
- Turn the key start switch to the ON position.
- Observe the status of the diagnostic code.
Expected Result:
The diagnostic code is active. See Diagnostic System Procedures, "Charging System".
Results:
- YES - The diagnostic code is active. Proceed to Test Step 3.
- NO - The diagnostic code is NOT active. Proceed to Test Step 2.
Test Step 2. CHECK THE CHARGING SYSTEM.
- Start the engine.
- Observe the status of the diagnostic code.
Expected Result:
The diagnostic code is active. See Diagnostic System Procedures, "Charging System".
Results:
- YES - The diagnostic code is active.
Repair: The charging system is charging at an excessive voltage. Check the charging system.
STOP
- NO - The diagnostic code is not active.
Repair: There is no problem at this time. Watch for a recurrence.
STOP
Test Step 3. CHECK THE BATTERY VOLTAGE.
- The engine is stopped. At the battery, measure the voltage.
Expected Result:
The voltage is less than 16 VDC.
Results:
- YES - The voltage is less than 16 VDC.
Repair: Exit this procedure and perform the diagnostic code procedure again. If the problem persists, the ECM may have failed. Prior to replacing an ECM, always contact your dealership's Technical Communicator for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM must be replaced, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace".
STOP
- NO - The voltage is not less than 16 VDC.
Repair: The charging system is charging at an excessive voltage. Check the charging system. See Diagnostic System Procedures, "Charging System".
STOP