Electronic Control Units are small computers within a vehicle that manage and control various electronic systems. They receive input from sensors throughout the vehicle, process the data, and then send signals to actuators to control functions like engine performance, transmission shifting, braking, and climate control. Modern vehicles contain multiple ECUs, each dedicated to specific systems, allowing for precise control and optimization. ECUs are critical for ensuring efficient, safe, and reliable vehicle operation, and they play a central role in advanced features like traction control, stability control, and adaptive cruise control.