What makes CAN robust enough for vehicles? Describe its error handling.

CAN layers several mechanisms. For detection: every frame has a CRC the receivers check; there are frame-format checks; bit-stuffing inserts an opposite bit after five identical bits, which both guarantees edges for resynchronization and lets nodes detect stuffing violations; transmitters monitor the bus and detect when what they sent doesn't match what's on the wire (bit errors); and an ACK slot lets any node that received a frame correctly assert dominant, so a transmitter learns at least one node heard it. When any node detects an error it transmits an error frame, which aborts the current message and triggers automatic retransmission, so transient errors are recovered without software involvement. The standout feature is fault confinement: each node maintains transmit and receive error counters and transitions through error-active, error-passive, and finally bus-off states as errors accumulate, so a malfunctioning node progressively reduces its bus participation and ultimately removes itself entirely, meaning one faulty node can't jam the whole network indefinitely. That combination of strong detection, automatic retransmission, and self-policing fault confinement, on top of noise-immune differential signaling, is why CAN is trusted in automotive and industrial safety contexts.