A faulty or malfunctioning transmission can trigger the check engine light for a handful of reasons, including things like an overheating gearbox or issues with the transmission control module ...

The Engine Control Module (ECM) is the computer responsible for controlling the engine. The ECM communicates with other vehicle control units via a communication bus.

A fix is now available for 2021 Cadillac CT5 sedans affected by an Engine Control Module (ECM) issue leading to non-reporting of catalytic converter faults.