Information Bus: Description and Operation
COMMUNICATIONS NETWORKStandard Corporate Protocol (SCP) Network
The SCP communications network allows communication between modules through a single vehicle-wide communications network. A single pair of twisted wires, SCP+ communications network and SCP- communications network, exchange bi-directional data messages between stand-alone modules. Multiple data signals can be transmitted over one circuit. Included in these messages is diagnostic data that is transmitted over the SCP+ communications network and SCP- communications network circuits to the data link connector (DLC).
Controller Area Network (CAN)
The CAN allows communication between the DLC and the diagnostic tool. A single pair of twisted wires, CAN+ and CAN-, exchange bi-directional data messages and allow transmission of multiple diagnostic data signals over 1 circuit.
International Standards Organization (ISO) 9141 Communications Network
The ISO 9141 communications network provides communication between the DLC and the diagnostic tool through a single circuit. The ISO 9141 communications network does not permit inter-module communication. The diagnostic tool initiates communication with the module undergoing testing, allowing transmission of diagnostic data to the diagnostic tool through the DLC.
Anti-Lock Brake System (ABS) Module
The ABS module communicates on the SCP communications network. The ABS module monitors the wheel speed readings from each anti-lock brake sensor and processes this information to determine an impending wheel lock-up. If a wheel lock-up is detected, the ABS module modulates the brake pressure to the appropriate brake caliper.
Front Electronic Module (FEM)
The FEM communicates on the SCP communications network. The FEM is a multi-function module which controls interior and exterior lighting and active anti-theft functions.
Rear Electronic Module (REM)
The REM communicates on the SCP communications network. The REM is a multi-function module which controls interior and exterior lighting and active anti-theft functions.
Restraint Control Module (RCM)
The RCM communicates on the ISO 9141 communications network. The RCM monitors and controls the supplemental restraint system (SRS). The SRS is designed to provide increased crash protection for front seat occupants. The RCM deploys the vehicle air bags based on sensor input during a crash event.
Instrument Cluster
The instrument cluster communicates on the SCP communications network. The instrument cluster contains a variety of warning lights and gauges that display vehicle specific information. This allows the driver to continually monitor vehicle conditions.
Remote Keyless Entry (RKE) Module
The RKE module communicates on the SCP communications network. The remote door locks and luggage compartment lid are controlled by the RKE module.
Powertrain Control Module (PCM)
The PCM is hardwired to 2 communications networks. Diagnostic data is provided through the CAN to the diagnostic tool. Stand-alone modules exchange information with the PCM through the SCP communications network. The PCM receives input from sensors and other electronic components (switches, relays). Based on the information received and programmed into its memory, the PCM generates output signals to control various relays, solenoids and actuators.
Dual Automatic Temperature Control (DATC) Module
The DATC module communicates on the SCP communications network. The DATC system automatically maintains a selected temperature for vehicle interior comfort and regulates the volume of airflow between the instrument panel registers, floor ducts, windshield defroster nozzle, and side window demisters.
Audio Control Module (ACM)
The ACM communicates on the SCP communications network. The ACM monitors the audio unit inputs. Based on these inputs, the ACM generates output signals to control the various audio system components which are designed to provided maximum listening pleasure.