To make system be more efficient, Body Control Module(hereinafter referred to BCM) applies CAN(Controller Area Network) communication system. CAN is a kind of communication system which can make related component share system information with just two line instead of complex individual signal line. It consists of related component and CAN BUS which consists of CAN_high line and CAN_low line. Each component can send and receive information by binary signal via CAN BUS. The related components for BCM are BCM, ADM, DDM and IMS(Seat, S/C)

To make communication be more accurate, every signal via CAN BUS contains error flame. Each component counts error and if accumulative error count in one node is above specified value, the ECM sets DTC ‘CAN BUSOFF’ and pertinent component is electronically separated.