ISO 9141 Communication Link

ISO 9141 Communication Link:

The ISO 9141 communication link:
- 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
- Active anti-theft
- Keyless entry
- Windshield wiper
- Power locks and windows
- Power steering
- Interior lighting control
- Semi-automatic ride control
- Warning indicator control

Fault Tolerance
The ISO 9141 communication link 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 ISO 9141 communication network internally.

Purpose
The information within this section is designed to diagnose ISO 9141 communication link 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 link concern, follow the diagnostic procedure in the order presented.

Module Identification
Modules included on this ISO 9141 communication link include:

Air Bag Diagnostic Monitor:
- Located behind the instrument panel to the right of the steering column.
- A failed air bag diagnostic monitor may cause no communication condition on ISO 9141 communication link.
- If communication to the air bag diagnostic monitor fails, refer to Air Bags (Supplemental Restraint Systems) for No Communication testing.

Anti-Lock Brake System (ABS) Control Module:
- Located under the battery tray in the lower left of the engine compartment.
- A failed anti-lock brake system module may cause no communication condition on ISO 9141 communication link.
- If communication to the anti-lock brake control module fails, refer to Antilock Brake System for No Communication testing.

Generic Electronic Module (GEM):
- Is plugged into the fuse junction panel.
- A failed GEM may cause a no communication condition on ISO 9141 communication link.
- If communication to the GEM fails, refer to the affected system for No Communication testing.

Remote Anti-Theft Personality (RAP) Module:
- Located under the instrument panel to the right of the steering column.
- A failed RAP module may cause no communication condition on ISO 9141 communication link.
- If communication to the RAP module fails, refer to Locks for No Communication testing.

Semi-Active Ride Control (SARC):
- Located in the luggage compartment on the front of the RH rear wheel housing.
- If communication to the semi-active ride control module fails, refer to Suspension for No Communication testing.