CONTROL GP-ELECTRONIC 9X9452 - Caterpillar

Illustration 1 g02064995The CID 0168 FMI 05 diagnostic code is associated with low current output of the alternator.The possible causes of this diagnostic code are listed below:
A charging system component has failed.
The machine harness is open.
The ECM may have failed, but 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, that all connections are secure and that all connections are 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. Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the problem has been corrected.Test Step 1. CHECK THE CHARGING SYSTEM AT HIGH IDLE
Start the engine. Run the engine at high idle.
Enter the diagnostic menu on the monitor. Observe the status of the diagnostic code. Expected Result:The diagnostic code is no longer active.Results:
YES - The diagnostic code is no longer active. Proceed to Test Step 2.
NO - The diagnostic code remains active. Proceed to Test Step 3.Test Step 2. CHECK THE CHARGING SYSTEM AT LOW IDLE
Start the engine. Run the engine at low idle.
Observe the status of the diagnostic code. Expected Result:The diagnostic code is no longer active.Results:
YES - The diagnostic code is no longer active. Watch for a recurrence.STOP
NO - The diagnostic code is active. The charging system is not charging at the proper level.Repair: If the engine low idle speed is too low, the alternator may not be producing the required output. Ensure that the engine low idle speed is correct and perform this test again. If the diagnostic code is still active, a charging system component may be faulty. Check the charging system. See Special Instruction, REHS0354, "Charging System Troubleshooting" for more information.STOPTest Step 3. CHECK FOR AN OPEN CIRCUIT
Turn the disconnect switch and the key start switch to the OFF position.
Disconnect the connector from the Monitor ECM. Disconnect the 403-GN(Green) wire from the alternator terminal with label "R".
Measure the resistance of wire 403-GN(Green) between the contact pin of the harness connector and the disconnected wire 403-GN(Green) at the alternator. Expected Result:The resistance should measure 5 ohms or less.Results:
YES - The resistance measures 5 ohms or less. The machine harness appears to be correct. Either the alternator is not working correctly or the ECM may be recording this diagnostic code incorrectly.Repair: Check the charging system. See Special Instruction, REHS0354, "Charging System Troubleshooting" for more information. If the voltage check of the charging system is correct, the ECM may have failed. A failure of the ECM is unlikely. Exit this procedure and perform this procedure again.If the cause of the diagnostic code is not found, proceed to Test Step 4.
NO - The resistance measurement is greater than 5 ohms. Wire 403-GN(Green) between the Monitor ECM and the alternator is open