BRACKET 6N3912 - Caterpillar

Note: Prior to beginning this procedure, inspect the harness connectors that are involved in this circuit. Poor connections may 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 the diagnostic code is active before performing a troubleshooting procedure.
Possible causes for an FMI 2 diagnostic code are:
A charging system component has failed.
Intermittent connection in the battery circuit for the ECM.
The ECM has failed. An ECM failure is unlikely.Possible Causes for an FMI 3 diagnostic code are:
The alternator output is above normal
The Machine ECM has failed. An ECM failure is unlikely.Possible Causes for an FMI 4 diagnostic code are:
The alternator output is below normal
The Machine ECM has failed. An ECM failure is unlikely.
Illustration 1 g06043663Note: The diagram above is a simplified schematic of the System Voltage connections. The schematic is electrically correct. However, not all the possible harness connectors are shown. Refer to the latest version of the Electrical Schematic .
Table 2
Troubleshooting Test Steps Values Results
1. Identify Active FMI Code Associated With The System Voltage Circuit
Code present. FMI 2 diagnostic code, proceed to Test Step 2.
FMI 3 diagnostic code, proceed to Test Step 4.
FMI 4 diagnostic code, proceed to Test Step 7.
Begin Process For FMI 2 Troubleshooting HERE
2. Test The Battery
A. Turn Key start switch to the ON position.
B.