Engine Control Units (ECUs) are digital computer systems integral to modern internal combustion engine management. Positioned within the vehicle’s engine compartment, ECUs receive data from numerous sensors—measuring parameters like temperature, pressure, and airflow—to precisely control ignition timing, fuel injection, and idle speed. Utilizing pre-programmed maps and real-time sensor input, the ECU optimizes engine performance, fuel efficiency, and emissions. Advanced ECUs incorporate diagnostic capabilities, storing diagnostic trouble codes (DTCs) for fault identification and utilizing communication protocols like CAN bus for vehicle network integration. Current designs increasingly integrate control of transmission functions and other vehicle systems.