Information Bus: Description and Operation
COMMUNICATIONS NETWORKPowertrain Control Module (PCM)
The PCM is on the controller area network (CAN). The PCM controls the engine for better fuel economy, emissions control, and failure mode detection and storage.
Restraint Control Module (RCM)
The RCM controls the deployment of the air bags based on sensor input. The RCM is on the CAN. The RCM communicates with the occupant classification sensor using the CAN. The occupant classification sensor does not communicate with the diagnostic tool, and is mentioned here as a possible concern should CAN communication be lost.
Anti-Lock Brake System (ABS)
Module The ABS module and the ABS module with stability assist are connected to the CAN. The ABS module controls the brake pressure to the 4 wheels to keep the vehicle under control while braking.
Instrument Cluster
The instrument cluster is connected to the CAN. The instrument cluster displays driver information, including tachometer reading, fuel level, engine coolant level and speed.
Occupant Classification Sensor
The occupant classification sensor is connected to the CAN. The occupant classification sensor is located in the passenger seat and is used to determine whether or not to deploy an airbag based on the weight detected in the passenger seat. The occupant classification sensor communicates on the CAN to the RCM only. Diagnosis is carried out through the RCM.
Generic Electronic Module (GEM)
The GEM is on the international standards organization (ISO) 9141 communications network.The GEM controls a variety of systems:
- windshield wipers
- warning chimes
- interior lamps
- exterior lamps
- power windows
- security