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.

Each module on the CAN serial data circuit learns the identity of the other modules on the circuit. If a module stops communicating after all modules have initiated for the ignition cycle, other modules set a DTC specific for the module not communicating:

DTC U2105, can not communicate with the ECM
DTC U2106, can not communicate with the TCM
DTC U2107, can not communicate with the BCM
DTC U2108, can not communicate with the EBCM

DTC U2105-U2108

Control Module	ID Number
Engine Control Module (ECM)	05
Transaxle Control Module (TCM)	06
Body Control Module (BCM)	07
Electronic Brake Control Module (EBCM)	08