Information Bus: Description and Operation
COMMUNICATIONS NETWORKPowertrain Control Module (PCM)
The PCM uses the controller area network (CAN). The PCM controls the engine for better fuel economy, emissions control and failure mode detection storage. The PCM also controls all of the passive anti-theft system (PATS) functions.
Check the CAN circuits between the PCM C175b and the data link connector (DLC) C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the CAN, damage to the DLC C251, damage to the PCM C175b, or a problem in the in-line connector.
Instrument Cluster
The instrument cluster uses both the CAN and the standard corporate protocol (SCP) communications networks. The instrument cluster displays a variety of vehicle system status information.
The instrument cluster shares the CAN termination responsibilities with the anti-lock brake system (ABS) module through the use of a split termination resistor.
The instrument cluster shares the SCP communications network termination responsibilities with the lighting control module (LCM) and the driver door module (DDM).
Check the CAN and SCP communications network circuits between the instrument cluster C220 and the DLC C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the CAN or SCP communications network, damage to the DLC C251, damage to the instrument cluster C220, or a problem in the in-line connector.
Anti-Lock Brake System (ABS) Module
The ABS module uses the CAN for communication with the diagnostic tool and other modules on the CAN. The ABS module controls the brake pressure to the 4 wheels to keep the vehicle under control while braking. The ABS module and the instrument cluster share CAN termination responsibilities with the use of a split termination resistor in each module.
Check the CAN circuits between the ABS module C135 and the DLC C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the CAN, damage to the DLC C251, damage to the ABS module C135, or a problem in the in-line connector.
Lighting Control Module (LCM)
The LCM uses the SCP communications network for communication with the diagnostic tool and other modules on the SCP communications network. The LCM, instrument cluster, and the DDM share the SCP communications network termination responsibilities. The SCP communications bus may remain operational when one of the termination resistors is not present.
The LCM controls the vehicle systems:
- warning chimes
- exterior lighting
- interior lighting
- backlighting
- perimeter alarm (if equipped)
Check the SCP communications network circuits between the LCM C2145a and the DLC C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the SCP communications network, damage to the DLC C251, or damage to the LCM C2145a.
Driver Door Module (DDM)
The DDM uses the SCP communications network. The DDM, instrument cluster, and the LCM share the SCP communications network termination responsibilities. The SCP communications bus may remain operational when one of the termination resistors is not present.
The module controls functions of the power windows, power locks, and remote keyless entry (RKE). The DDM also communicates with the driver seat module (DSM) to control the power seat and mirror memory functions. If equipped, both the DDM and LCM communicate to control the perimeter alarm functions.
Check the SCP communications network circuits between the DDM C501a and the DLC C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the SCP communications network, damage to the DLC C251, or damage to the DDM C501a.
Driver Seat Module (DSM)
The DSM uses the SCP communications network. The DSM controls the positioning and programming of the driver seat, pedals and both outside mirrors.
Check the SCP communications network circuits between the DSM C341c and the DLC C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the SCP communications network, damage to the DLC C251, or damage to the DSM C341c.
Air Suspension Module
The air suspension module uses the SCP communications network. The air suspension module controls the rear ride height.
Check the SCP communications network circuits between the air suspension module C2131b and the DLC C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the SCP communications network, damage to the DLC C251, or damage to the air suspension module C2131b.
Climate Control Assembly
The climate control assembly uses the SCP communications network. The climate control assembly maintains and controls the automatic climate functions that maintain the vehicle at a constant temperature setting.
Check the SCP communications network circuits between the climate control assembly C228b and the DLC C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the SCP communications network, damage to the DLC C251, or damage to the climate control assembly C228b.
Remote Audio/Climate Control Module
The remote audio/climate control module uses the SCP communications network. The remote audio/climate control module allows passengers in the rear seat to control the climate control and the audio unit functions using a rear mounted control switch.
Check the SCP communications network circuits between the remote audio/climate control module C3160a and the DLC C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the SCP communications network, damage to the DLC C251, or damage to the remote audio/climate control module C3160a.
Navigation Module
The navigation module uses the SCP communications network for diagnostic communications, and a separate audio CAN to communicate with the navigation display unit.
Check the SCP communications network circuits between the navigation module C4209 and the DLC C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the SCP communications network, damage to the DLC C251, or damage to the navigation module C4209.
Restraint Control Module (RCM)
The RCM uses the international standards organization ISO 9141 communications network. The RCM controls the deployment of the air bags based on sensor input.
Check the ISO 9141 communications network circuit between the RCM C310a and the DLC C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the ISO 9141 communications network, damage to the DLC C251, or damage to the RCM C310a.
Parking Aid Module
The parking aid module uses the ISO 9141 communications network. The module uses sensors in the rear bumper that detect close objects when the vehicle is in REVERSE.
Check the ISO 9141 communications network circuit between the parking aid module C4014 and the DLC C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the ISO 9141 communications network, damage to the DLC C251, or damage to the parking aid module C4014.
Luggage Compartment Lid Module
The luggage compartment lid module uses the ISO 9141 communications network. The module controls the motor that opens and closes the luggage compartment lid.
Check the ISO 9141 communications network circuit between the luggage compartment lid module C4081a and the DLC C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the ISO 9141 communications network, damage to the DLC C251, or damage to the luggage compartment lid module C4081a.