An engine control unit (ECU) is an electronic device that manages various functions of an internal combustion engine. It monitors data from sensors, such as temperature and air pressure, to optimize engine performance, fuel efficiency, and emissions. The ECU adjusts parameters like fuel injection and ignition timing to ensure the engine runs smoothly. Modern vehicles often have multiple ECUs, each responsible for different systems, such as transmission, braking, and infotainment. These units communicate with each other to enhance overall vehicle performance and safety. Advances in technology have made ECUs more sophisticated, allowing for better diagnostics and control over engine functions.