Information Bus: Description and Operation
COMMUNICATIONS NETWORKPowertrain Control Module (PCM)
The PCM uses the high speed controller area network (CAN) for communication with the diagnostic tool and other modules on the high speed CAN. The PCM controls the engine for better fuel economy, emissions control, failure mode detection and storage, and engine disable for the passive anti-theft system (PATS) functions. The engine off natural vacuum (EONV) module (if equipped) is located within the PCM module.
The PCM and the instrument cluster share high speed CAN termination responsibilities with the use of a split termination resistor in each module.
Check the high speed CAN circuits between the PCM C175b 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 high speed CAN, damage to the DLC C251, damage to the PCM C175b, or a problem in an in-line connector.
Transmission Control Module (TCM) - 6R60 Transmission
If equipped, the TCM (part of the metachromatic assembly) uses the high speed CAN for communication with the diagnostic tool and other modules on the high speed CAN. The TCM controls transmission shifting, the electronic pressure control solenoid, and the torque converter clutch.
Check the high speed CAN circuits between the TCM C199 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 high speed CAN, damage to the DLC C251, damage to the TCM C199, or a problem in an in-line connector.
Anti-Lock Brake System (ABS) Module
The ABS module uses the high speed CAN for communication with the diagnostic tool and other modules on the high speed CAN. The ABS module controls the brake pressure to the 4 wheels to keep the vehicle under control while braking.
Check the high speed CAN circuits between the ABS module C155 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 high speed CAN, damage to the DLC C251, damage to the ABS module C155, or a problem in an in-line connector.
Restraint Control Module (RCM)
The RCM uses the high speed CAN for communication with the diagnostic tool and other modules on the high speed CAN. The RCM controls the deployment of the air bags based on sensor input.
Check the high speed CAN circuits between the RCM C310b 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 high speed CAN, damage to the DLC C251, damage to the RCM C310b, or a problem in an in-line connector.
Occupant Classification Sensor
The occupant classification sensor uses the high speed CAN for communication with the diagnostic tool and other modules on the high speed CAN. The occupant classification sensor provides the status of the front passenger seat occupant to the RCM for controlling the deployment of the passenger air bag based.
Check the high speed CAN circuits between the occupant classification sensor C3159 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 high speed CAN, damage to the DLC C251, damage to the occupant classification sensor C3159, or a problem in an in-line connector.
Four-Wheel Drive (4WD) Control Module
The 4WD control module (if equipped) uses the high speed CAN for communication with the diagnostic tool and other modules on the high speed CAN. The 4WD control module monitors and regulates the four wheel drive operation.
Check the high speed CAN circuits between the 4WD control module C281b 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 high speed CAN, damage to the DLC C251, damage to the 4WD control module C281b, or a problem in an in-line connector.
Instrument Cluster
The instrument cluster uses both the high speed CAN and the medium speed CAN. The instrument cluster displays a variety of information as well as providing a gateway for information transfer between both the high speed and medium speed CAN. The instrument cluster is also the primary control module for all PATS functions.
The instrument cluster and the PCM share the high speed CAN termination responsibilities with the use of a split termination resistor in each module.
The instrument cluster and the smart junction box (SJB) share medium speed CAN termination responsibilities with the use of a split termination resistor in each module.
Check both the high speed and medium speed CAN 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, damage to the DLC C251, damage to the instrument cluster C220, or a problem in an in-line connector.
Smart Junction Box (SJB)
The SJB uses the medium speed CAN for communication with the diagnostic tool and other modules on the medium speed CAN. The SJB is equipped on all vehicles and is a combination of a multifunction module and an interior power junction box. The SJB controls multiple systems, which include:
- exterior lamps
- illuminated entry
- interior lamps
- power door locks
- smart locks
- remote keyless entry RKE system
Check the medium speed CAN circuits between the SJB C2280d 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 medium speed CAN, damage to the DLC C251, damage to the SJB C2280d, or a problem to an in-line connector.
Parking Aid Module
The parking aid module (if equipped) is connected to the medium speed CAN. The module controls sensors in the rear bumper that detect close objects when the vehicle is in reverse.
Check the medium speed CAN circuits 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 medium speed CAN, damage to the DLC C251, damage to the parking aid module C4014, or a problem to an in-line connector.
Driver Seat Module (DSM)
The DSM module (if equipped) uses the medium speed CAN for communication with the diagnostic tool and other modules on the medium speed CAN. The DSM controls the position of the driver power seat, and the power outside rear view mirrors.
Check the medium speed CAN circuits between the DSM C3299c 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 medium speed CAN, damage to the DLC C251, damage to the DSM C3299c, or a problem to an in-line connector.
Electronic Automatic Temperature Control (EATC) Module
The EATC module (if equipped) uses the medium speed CAN for communication with the diagnostic tool and other modules on the medium speed CAN. The EATC module controls the automatic climate functions that maintain the vehicle interior temperature at a constant setting.
Check the medium speed CAN circuits between the EATC module C228a 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 medium speed CAN, damage to the DLC C251, damage to the EATC module C228a, or a problem to an in-line connector.
Retractable Running Board Module
The retractable running board module (if equipped) uses the medium speed CAN for communication with the diagnostic tool and other modules on the medium speed CAN. The retractable running board module controls the operation of the vehicle running boards.
Check the medium speed CAN circuits between the retractable running board module C4322b 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 medium speed CAN, damage to the DLC C251, damage to the retractable running board module C4322b, or a problem to an in-line connector.
Audio Unit and Audio Unit With Navigation
The audio unit and the audio unit with the navigation system (if equipped) uses the medium speed CAN for communication with the diagnostic tool and other modules on the medium speed CAN.
Check the medium speed CAN circuits between the audio unit C290b 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 medium speed CAN, damage to the DLC C251, damage to audio unit C290b, or a problem to an in-line connector.
Satellite Radio Receiver
The satellite radio receiver (if equipped) uses the medium speed CAN for communication with the diagnostic tool and other modules on the medium speed CAN.
Check the medium speed CAN circuits between the satellite radio receiver C3290 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 medium speed CAN, damage to the DLC C251, or damage to satellite radio receiver C3290, or a problem to an in-line connector.
Digital Versatile Disk (DVD) Player
The DVD player (if equipped) uses the medium speed CAN for communication with the diagnostic tool. The DVD player is part of the family entertainment system.
Check the medium speed CAN circuits between the DVD player C949 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 medium speed CAN, damage to the DLC C251, damage to DVD player C949, or a problem to an in-line connector.