Information Bus: Description and Operation

COMMUNICATIONS NETWORK

Anti-Lock Brake System (ABS) Module
The ABS module is on the controller area network (CAN). The ABS module controls the brake pressure to the 4 wheels to keep the vehicle under control while braking. The ABS module also controls the stability assist and traction control systems (if equipped).

Driver Seat Module (DSM)
The DSM is on the universal asynchronous receiver-transmitter (UART)-based protocol (UBP) communications network. The DSM controls the positioning and programming of the driver seat and memory pedals.

Electronic Automatic Temperature Control (EATC) Module
The EATC module is on the CAN. The EATC module controls the dual automatic climate functions that maintain the vehicle interior temperature at a constant setting.

Instrument Cluster
The instrument cluster is on both the CAN and the UBP communications networks. The instrument cluster uses the CAN for communication with the diagnostic tool. The UBP communications network is used by the instrument cluster for communication with other modules on the UBP communications network. The instrument cluster also passes some information from the CAN modules to modules on the UBP communications network for inter-module communications. It is an analog face cluster with a digital odometer. The instrument cluster displays a variety of information.

Parking Aid Module
The parking aid module is connected to the international standards organization (ISO) 9141 communications network. The module controls sensors in the rear bumper that detect close objects when the vehicle is in reverse.

Powertrain Control Module (PCM)
The PCM is on the CAN and uses this network to communicate with the diagnostic tool. The PCM utilizes an internal termination resistor for normal interface with the CAN. Damage or loss of this termination resistor results in intermittent operation and or failure of the entire CAN. The PCM controls the engine for better fuel economy, emissions control, failure mode detection and storage, all passive anti-theft system (PATS) functions, as well as all 4-wheel drive (4WD) and speed control functions. Refer to Computers and Control Systems for diagnosis and testing of the PCM.

Restraint Control Module (RCM)
The RCM is on the ISO 9141 communications network. The RCM controls the deployment of the air bags based on sensor input.

Tire Pressure Monitoring System Module
The tire pressure monitoring system module is on the CAN. The tire pressure monitoring system module uses one sensor mounted in each tire to sense low tire pressure. When low tire pressure is sensed the module will send a warning to the driver.

Vehicle Security Module
The vehicle security module is on the UBP communications network. The vehicle security module controls the remote keyless entry (RKE) functions for the vehicle.