Class 2 Bus

The class 2 bus is a vehicle-wide communications link. This class 2 link is mandated by the federal government for use on on-board-power mirror diagnostics (OBD) of the Powertrain Control Module (PCM). The use of this bus has been expanded to include most of the modules on this vehicle. The mirror system utilizes the class 2 bus for messages between the Remote Function Actuator (RFA) and the DDM. A class 2 bus message is also used to relay the transmission gear position for memory recall use. The RFA is the receiving device for keyless entry. The RFA keyless entry transmitters broadcast codes to identify which keyless entry transmitter, or driver, has unlocked the vehicle. The driver identity message is sent over the class 2 bus to the DDM, and other modules, to reposition all personalized vehicle features for that driver.