What What is ECM? Means:
The Electronic Control Module (ECΜ) or Engine Control Module (ECΜ) also known as Powertrain Control Module (PCM), is a computer that manages the engine's Ignition, Fuel Injection, and Emission Systems. In some vehicles, it may also control the operation of the Transmission and Anti-Lock Brake Systems as well.
Engine Control Module (ECΜ) Example