What is PCM? The Powertrain Control Module (PCM) is an advanced version of the ECU that not only controls the engine but also oversees the transmission, drivetrain, and other related systems. This integrated approach allows for better coordination and overall vehicle performance. Electronic Control Unit (ECU), Powertrain Control Module (PCM), and Engine Control Module (ECM) are all terms used to refer to the central computer system in your vehicle that controls various functions related to t...