Electronic control unit

An ECU from a Geo Storm.

In automotive electronics, an electronic control unit (ECU), also called a control unit, or control module, is an embedded system that controls one or more of the electrical systems or subsystems in a vehicle. Some modern cars have up to 80 ECUs, including:

• Engine Control Unit - also known as an ECU
• Transmission Control Unit - TCU
  • the above two may be combined, and referred to as a Powertrain Control Module (PCM)
• Airbag control unit - ACU
• Telephone Control Unit - TCU
• Man Machine Interface - MMI
• Door Control unit
• Seat Control Unit
• Climate Control Unit
• speed control unit
• Convenience control unit - CCU

Managing the increasing complexity of ECUs and number of ECUs in a vehicle has become a key challenge for OEMs.

ECU -often called the brain of a car

In some older vehicles, the ECU is referred to as an ECM (electronic control module).