A car’s control units talk over CAN, FlexRay and LIN buses. MSG Equipment explains the features and differences of these protocols.
Even budget cars now carry many electronic control units, which exchange data as synchronised signals over dedicated buses.
- CAN: the first standard protocol between ECUs; real-time capable, low-cost and with robust error handling, but its speed and 8-byte payload per message are limiting for modern active safety.
- FlexRay: CAN’s successor, with higher data rates and larger payloads and time-triggered communication; used in safety-critical systems and adaptive cruise control in premium cars.
- LIN: a simpler, low-cost bus for auxiliary systems.
Understanding these buses matters when diagnosing systems such as electric power steering.