ECU

An Electronic Control Unit (ECU) is a compact embedded computer that controls a specific electrical subsystem or function in vehicles, aircraft, industrial equipment, or household appliances. In automotive contexts, ECU is a generic term for modules that read sensors and drive actuators. Common automotive ECUs include the engine control unit (engine management), powertrain control module, transmission control unit, brake control module, and body or climate control modules. Modern vehicles may house multiple ECUs interconnected over in-vehicle networks such as CAN, LIN, or FlexRay.

ECUs operate by running firmware or software that processes sensor inputs, executes control algorithms, and output commands to actuators. Sensor data may include oxygen concentration, mass air flow or manifold pressure, throttle position, crankshaft position, and wheel speed. Actuators include fuel injectors, ignition coils, solenoids, actuators for variable valve timing, and braking or airbag actuators. Real-time processing and calibration data stored in nonvolatile memory enable precise control. Onboard diagnostics and fault reporting, accessible through standards such as OBD-II, are used to identify malfunctions.

Outside automotive use, ECUs are common as generic embedded controllers in industrial and consumer electronics. In historical and financial contexts, ECU stands for the European Currency Unit, a unit of account used by the European Community before the euro was introduced.