ECUs

Electronic control unit (ECU) refers to any embedded device in a vehicle that manages a specific electrical system or subsystem. An ECU typically comprises a microcontroller or microprocessor, memory, input/output interfaces, and firmware. It processes sensor information, executes control algorithms, and issues commands to actuators, enabling functions from fuel injection and ignition timing to braking, climate control, and door locking.

Vehicles today often house multiple ECUs distributed across systems such as engine, transmission, chassis, body electronics, and safety subsystems. These ECUs communicate over in-vehicle networks to coordinate behavior while allowing diagnostics and reprogramming. Common network technologies include Controller Area Network (CAN), Local Interconnect Network (LIN), FlexRay, and Automotive Ethernet, each with different bandwidth, real-time, and determinism characteristics.

ECUs can range from simple, single-function modules to complex, multipurpose controllers. Some functions are centralized in a few powertrain or gateway ECUs, while others remain distributed to enhance modularity and fault tolerance. Development emphasizes reliability, real-time performance, and safety. Many ECUs operate with real-time operating systems and must comply with automotive standards, such as ISO 26262 for functional safety. Calibration, adaptation, and parameter storage allow tuning of performance for different markets and engines.

Diagnostics and maintenance are supported through standards like OBD-II and Unified Diagnostic Services (UDS). With the rise of electrification and automated driving, ECUs are increasingly powerful, capable of over-the-air updates, and require attention to cybersecurity and software lifecycle management.