What does a PCM (Powertrain Control Module) monitor?

The Powertrain Control Module (PCM) is a crucial component in a vehicle's engine management system. It primarily oversees the performance of both the fuel injection and ignition systems, ensuring optimal engine operation. Additionally, the PCM is responsible for monitoring emissions systems to comply with environmental regulations. This integrated role helps in determining the right amount of fuel to inject into the engine and managing ignition timing for efficient combustion, which in turn affects vehicle performance, fuel economy, and emissions.

Transmission fluid levels, tire pressure, and battery voltage are monitored by other systems within the vehicle. For instance, transmission fluid levels are usually managed by the transmission control module, tire pressure is monitored by the tire pressure monitoring system (TPMS), and battery voltage is typically overseen by the vehicle's onboard charging system or a dedicated battery management system. Hence, the PCM's primary focus is on the components related to fuel and ignition, which enhances its role in controlling the powertrain systems effectively.