CID 1638 CAT Fault Code

Cause :

The battery supplies electricity to the TCM even when the ignition switch is off. This power allows the TCM to store data such as DTC history and freeze frame data.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.