CID 1646 CAT Fault Code

Cause :

When the ignition switch is turned to ON, voltage from the ECM's MREL terminal is applied to the EFI MAIN relay. This causes the contacts of the EFI MAIN relay to close, which supplies power to terminal +B of the TCM.It starts at the battery, includes ignition switch, fuses, starter solenoid, starter relay, and multiple safety devices, such as clutch position sensor and the neutral safety switches.