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.If the charge system light stays on, or comes on while driving, there may be a problem with the electrical charging system. Driving while this light is on could drain the battery.
Don't forget ! When a fault code pops up, CAT's Uptime Center is automatically notified via an cellular link, and it alerts the truck's owner by prearranged methods, usually email or phone calls.