Circuit Description
WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The controller area network (CAN) serial data line is a high speed serial data bus used to communicate information between the engine control module (ECM), body control module (BCM), electronic brake control module (EBCM), and the transmission control module (TCM). Typical data-transmission speeds must be high enough to ensure that the required real-time response is maintained.
The CAN serial data line does not communicate with the scan tool via the DLC. CAN serial data information is interpreted by the BCM and transmitted to the serial data line by the BCM.
The CAN circuits are monitored continuously by the modules on the circuit. The only requirement is that the modules are in an ON power mode.