ALTERNATOR A. 0671948 - Caterpillar

Illustration 1 g01227979
Schematic of the transmission controlThis diagnostic code is associated with the transmission downshift switch. The transmission downshift switch is connected to two inputs of the Power Train ECM. One contact is open and the other contact is grounded during proper operation.The FMI 04 means that the ECM has determined that both circuits are grounded.Note: The following test procedure may create other diagnostic codes. Ignore these diagnostic codes and clear these diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 0621 FMI 04 is active before performing this procedure.
Table 1
Downshift Switch    
Switch Position    G762-BR Circuit
N/O J1-40 (1)    G761-YL Circuit
N/C J1-41 (2)    
Depressed     Closed     Open    
Released     Open     Closed    
( 1 ) N/O means Normally Open.
( 2 ) N/C means Normally Closed.Test Step 1. CHECK THE SWITCH
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness from the switch.
Turn the key start switch and the disconnect switch to the ON position.Expected Result:The CID 0621 FMI 04 has been replaced by CID 0621 FMI 03.Results:
YES - The CID 0621 FMI 04 has been replaced by CID 0621 FMI 03. The machine harness and the ECM are correct. Proceed to Test Step 3.
NO - The CID 0621 FMI 04 is still active. Proceed to Test Step 2.Test Step 2. CHECK THE HARNESS
Turn the disconnect switch and the key start switch to the OFF position.
The machine harness remains disconnected from the switch.
Disconnect the machine harness connector(s) from the ECM.
At the machine harness connector for the ECM, measure the resistance from contact J1-41 (wire G761-YL) of the machine harness to all the contacts that are used in the machine harness connectors for the ECM.
At the machine harness connector for the ECM, measure the resistance from contact J1-40 (wire G762-BR) of the machine harness to all the contacts that are used in the machine harness connectors for the ECM.Expected Result:Each resistance measurement is greater than 5 ohms.Results:
YES - Each resistance measurement is greater than 5 ohms. Proceed to Test Step 3.
NO - One or more of the measurements were less than 5 ohms. There is a short in the machine harness.Repair: The short is between wire G761-YL and the circuit with the lowest resistance measurement, or the short is between wire G762-BR and the circuit with the lowest resistance measurement. Repair the machine harness or replace the machine harness.STOPTest Step 3. CHECK THE OPERATION OF THE SWITCH
The machine harness remains disconnected from the switch.
Measure the resistance between contact 2 (wire 202-BK) and contact 7 (wire D732-YL) of the harness connector for the switch.
Measure the resistance between contact 2 (wire 202-BK) and contact 8 (wire D733-BR) of the harness connector for the switch.Expected Result:The resistance from contact 2 to contact 7 is less than