An ECU, or Electronic Control Unit, is a crucial component in modern vehicles. It is a small computer that manages various functions, such as engine performance, transmission, and safety systems. Each ECU is programmed to monitor and control specific tasks, ensuring that the vehicle operates efficiently and safely. There are multiple types of ECUs in a vehicle, including the Engine Control Module (ECM), which regulates engine functions, and the Transmission Control Module (TCM), which manages gear shifting. Together, these units communicate through a network, allowing for real-time adjustments and improved vehicle performance.