Diagnostic Communication Network

System Components

The Diagnostic Communication Network system:
- consists of a single wire, Circuit 70 (LB/W).
- provides a common link for communication to an off-board tester through the Data Link Connector (DLC) located under the instrument panel to the right of the steering column.
- does not allow module-to-module communications.

The micro-processor based subsystems included on this network are:
- anti-lock brake
- supplemental air bag restraints
- Remote Anti-theft Personality (RAP) module
- windshield wiper
- power locks and windows
- power steering
- interior lighting control
- Semi-Automatic Ride Control (SARC)
- warning indicator control

FAULT TOLERANCE
The diagnostic communication network will fail if any of the following occur:
- circuit 70 (LB/W) shorted to ground.
- circuit 70 (LB/W) shorted to battery positive voltage (B+).
- the module loses power or ground supply.
- a module failure shorts the diagnostic communication network internally.

PURPOSE
The information is designed to diagnose any diagnostic communication network concerns.

These concerns may:
- affect normal functional operations of the vehicle.
- be directly related to customer concerns.
- be undetectable except during diagnostics.

To properly diagnose a network concern, follow the diagnostic procedure in the order presented.

MODULE IDENTIFICATION
Modules included on this diagnostic communication network include:

Electronic Crash Sensor (ECS):
- located behind the instrument panel to the right of the steering column.
- a failed Electronic Crash Sensor (ECS) may cause a no communication condition on the diagnostic communication network.
- if communication to the ECS fails, refer to Air Bags (Supplemental Restraint systems) to diagnose ECS related concerns.

Anti-Lock Brake System (ABS) Control Module:
- located under the battery tray in the lower left of the engine compartment.
- a failed ABS module may cause a no communication condition on the diagnostic communication network.
- if communication to the ABS module tails, refer to Anti-Lock Brake System to diagnose ABS module related concerns.

Generic Electronic Module (GEM):
- is plugged into the fuse junction panel.
- a failed GEM may cause a no communication condition on the diagnostic communication network.
- if communication to the GEM fails, refer to the affected sub-system (such as Wiper and Washer Systems or Courtesy Lamps etc.) for No Communication testing.

Remote Anti-Theft Personality (RAP) Module:
- located under the instrument panel to the right of the steering column.
- a failed Remote Anti-Theft Personality (RAP) module may cause a no communication condition on the diagnostic communication link.
- if communication to the RAP module fails, refer to Keyless entry for RAP Module related concerns.

Semi-Active Ride Control (SARC):
- located in the luggage compartment on the front of the RH rear wheel housing.
- if communication to the SARC module tails, refer to Automatic Suspension to diagnose SARC module related concerns.