System Description

ECM, TCM (A/T model), ABS/ESP® control module, BCM, combination meter, 4WD control module (motor-shift type 4WD model), HVAC control module, keyless start control module (keyless start model), SDM (advanced air bag model), ID controller (Canadian specification) and steering angle sensor (ESP® model) of this vehicle communicate control data between each control module.

Communication of each control module is established by CAN (Controller Area Network) communication system. CAN communication system uses the serial communication in which data is transmitted at a high speed. It uses a twisted pair of two communication lines (CAN High/CAN Low) for the high-speed data transmission. As one of its characteristics, multiple control modules can communicate simultaneously. In addition, it has a function to detect a communication error automatically. Each module reads necessary data from the received data and transmits data.

The system is structured in such way that other control modules/sensors are connected (hooked) to CAN main bus (CAN main circuit) between ECM and combination meter. ECM and combination meter have a built-in terminating resistance to stabilize the entire CAN bus (CAN circuit). If either module is disconnected or any abnormality (open or shorted CAN circuit) occurs, CAN bus as a whole becomes unstable and causes malfunction of CAN communication between modules.