SEAL G 4W5201 - Caterpillar

Possible Causes and Schematics
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 Transmission/Chassis ECM has failed. A failure of the ECM is unlikely.The FMI 2 error code will only be logged under the following conditions:
Three voltage readings that are below 18 VDC or above 32 VDC in a period of 7 seconds.
The key switch is in the ON position.
The engine is running.
The engine is not cranking.Possible Causes for an FMI 3 diagnostic code are:
A charging system component has failed.
The harness wiring has failed.
The Transmission/Chassis ECM has failed. A failure of the ECM is unlikely.Possible Causes for an FMI 4 diagnostic code are:
A charging system component has failed.
The harness wiring has failed.
The Transmission/Chassis ECM has failed. A failure of the ECM is unlikely.The FMI 4 error code will be logged when the system voltage is less than 9.0 VDC.
Illustration 1 g03393834
Note: The diagram above is a simplified schematic of the System Voltage connections. The schematic is electrically correct. However, not all of the possible harness connectors are shown. Refer to the latest revision of Electrical Schematic, UENR3204 for the complete schematic of machines with a serial number prefix of (S/N: TFB). For machines with a serial number prefix of LFB refer to Electric Schematic, UENR3205.Troubleshooting Procedure
Table 2
Troubleshooting Test Steps    Values    Results    
1. Identify Active FMI Code Associated With The Electrical Power Supply     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 DTC 168-2 Troubleshooting HERE    
2. Test the Battery
A. Turn Key start switch to the ON position.
B. Observe the status of the diagnostic code.    
The diagnostic code is NOT active.     OK - The diagnostic code is NOT active.
Proceed to Test Step 3.
NOT OK - The diagnostic code is active.
Repair: See Special Instruction, SEHS7633, "Battery Test Procedure".
STOP    
3. Check If The Diagnostic Code Is Still Active
A. Inspect the harness connectors. Clean the contacts of the harness connectors. Check the wires for damage to the insulation that is caused by excessive heat, battery acid, or chafing.
B. Perform a
45 N (10 lb) pull test on each of the wires that are associate with the circuit.
C. Reconnect all harness connectors to make sure that the connectors are fully seated. Also, make sure that the clips for each connector are fastened.
D. Turn the disconnect switch and the key start switch to the ON position.
E. Operate the machine.
F. Determine if the diagnostic code is active.    
Diagnostic code is no longer active.     OK - Diagnostic code is no longer active. The initial diagnostic code was probably caused by a poor electrical connection. The problem does not exist at this time. Resume normal machine operation.
NOT OK - Diagnostic code remains active. The problem has not been corrected.
Repair : Check the circuit again as ECM failure is unlikely. Exit the procedure and perform