An electronic control unit (ECU) is any embedded system in automotive electronics that controls one or more electrical systems or subsystems in a vehicle.

Types of ECUs include electronic control unit, engine control module (ECM), powertrain control module (PCM), transmission control module (TCM), brake control module (BCM or EBCM), central control module (CCM), central Timing Module (CTM), Universal Electronic Module (GEM), Body Control Module (BCM), Suspension Control Module (SCM), Control Unit or Control Module. In summary, these systems are sometimes referred to as car computers (technically no single computer, but multiple computers.) Sometimes an assembly contains several separate control modules (PCMs are typically engines and transmissions).

Some modern motor vehicles have up to 80 ECUs. The number, complexity and complexity of embedded software in ECUs continues to increase. [2] Managing the increasing complexity and number of ECUs in vehicles has become a major challenge for original equipment manufacturers (OEMs).