Communications Network

COMMUNICATIONS NETWORK

The communications network consists of the following components:
- standard corporate protocol (SCP) communication network
- international standards organization (ISO 9141) communication network
- The universal asynchronous transmitter-receiver (UART)-based protocol (UBP) communications network
- data link connector (DLC)
- lighting control module (LCM)
- message center module
- electronic automatic temperature control (EATC) module
- instrument cluster
- speed control actuator
- driver door module (DDM)
- driver seat module (DSM)
- powertrain control module (PCM)
- restraint control module (RCM)
- anti-lock brake control (ABS)
- rear air suspension module
- luggage compartment lid module
- parking aid module
- audio control module (ACM)
- navigation system module

PRINCIPLES OF OPERATION

The vehicle has 3 module communication networks:
- The standard corporate protocol (SCP) communications network.
- The international standards organization (ISO) 9141 communications network.
- The universal asynchronous transmitter-receiver (UART)-based protocol (UBP) communications network.

The diagnostic tool connects to all three networks through the data link connector (DLC). This makes diagnosis and testing of these systems easier by allowing one diagnostic tool to be able to diagnose and control any module on the three networks from one connector. The DLC can be found under the instrument panel between the steering column and the radio.

The ISO 9141 communications network does not permit intermodule communication. When the diagnostic tool communicates to modules on the ISO 9141 communication network, the diagnostic tool must request all information; or initiate module commands.

The ISO 9141 communications network will not function if the wire is shorted to ground or battery voltage. Also, if one of the modules on the ISO 9141 communications network loses power or shorts internally, communications to that module will fail.

The SCP communications network will remain operational even with the severing of one of the bus wires. Communications will also continue if one of the bus wires is shorted to ground or voltage, or if some but not all termination resistors are lost.

The UBP communications network will not function if the wire is shorted to ground or voltage. The UBP is different from the ISO communication network in that it allows intermodule communication.

4-Wheel Anti-Lock Brake System/Traction Control (ABS/TC) Control Module Or Stability Assist Module (if equipped)
The anti-lock brake system (ABS) control module is on the SCP communication network. The ABS control module controls the brake pressure to the 4 wheels to keep the vehicle under control while braking.

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

Message Center Module
The message center module is connected to the SCP communication network. The message center module computes and displays oil life, and compass heading.

Parking Aid Module
The parking aid module is connected to the UBP 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 powertrain control module (PCM) is connected to the SCP communication network. The PCM controls the engine for better fuel economy, emissions control and failure mode detection storage.

Audio Control Module (ACM)
The audio control module (ACM) is connected to the SCP communication network and also to the audio control protocol (ACP) communication network. The ACM communicates with the compact disc player/changer and the rear seat controls module using the ACP network. If equipped, the rear seat audio/climate controls are located in the rear seat armrest. The ACM uses the SCP network for diagnostics.

Audio Control Module (ACM) w/ Navigation Display & built-in 6 CDDJ
The audio control module (ACM) is connected to the controller area network (CAN) communication network and also to the audio control protocol (ACP) communication network. The ACM communicates with the rear seat controls module using the ACP network. If equipped, the rear seat audio/climate controls are located in the rear seat armrest. The ACM uses the CAN network to communicate with the navigation system module.

Lighting Control Module (LCM)
The lighting control module (LCM) is on the SCP communication network. The LCM controls both interior and exterior lighting and warning chimes.

Instrument Cluster
The instrument cluster is on the SCP communication network. The instrument cluster has an analog face cluster with a digital odometer. The instrument cluster displays a variety of information.

Driver Seat Module (DSM)
The driver seat module (DSM) is on the SCP communication network. The DSM controls the positioning and programming of the driver seat, pedals and both outside mirrors.

Speed Control Actuator
The speed control actuator is on the SCP communication network. The speed control actuator, when activated, controls and maintains vehicle speed by actuating the throttle linkage.

Luggage Compartment Lid Module
The luggage compartment lid module is on the ISO 9141 network. The module controls the motor that opens and closes the luggage compartment lid.

Driver Door Module (DDM)
The driver door module (DDM) is connected to the SCP communication network. The module controls many functions including power windows, power locks, and remote keyless entry. The DDM also communicates with the driver seat module (DSM) to control power seat and mirror memory.

Rear Air Suspension Module
The rear air suspension module is connected to the SCP communication network. The rear air suspension module controls the rear ride height.

Electronic Automatic Temperature Control (EATC) Module
The electronic automatic temperature control (EATC) module is connected to the SCP communication network. The EATC module controls automatic climate functions that maintain the vehicle at a constant temperature setting.

Navigation System Module
The navigation system module is on the SCP communication networks. The navigation system module uses the SCP communication network for diagnostic communications, and the medium speed CAN communication network to communicate with the ACM/navigation display unit. The vehicle navigation system provides a feature that will guide the user to any entered destination. The system uses the global positioning sensor (GPS), vehicle speed, and other sensor information to accurately establish the vehicle position. The navigation system module compares this position to the CD-ROM vector map. The system then provides the maneuvers required during the journey in order to arrive at the destination entered.