FMI 233 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.The most common mistake when addressing this code is replacing the starter or PCM when the damage is in the wiring or other components. Thus, it's extremely important to conduct a thorough diagnosis before replacing anything to avoid unnecessary replacements of parts.