The full name of engine ECM is: engine control module, namely "engine control module". It is generally called "ECU" in the industry at present: electronic control unit, that is, electronic control unit.
Simply put, the control system of electronically controlled engine consists of three parts: sensor, electronic control unit ECU and actuator, among which ECU plays the role of "brain" and is a special microcomputer controller for engine. Like an ordinary computer, it consists of a microprocessor (CPU), a memory (ROM, RAM), an input/output interface (I/O), an analog-to-digital converter (A/D) and a large-scale integrated circuit such as shaping and driving.