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 is designed to diagnose IS0 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

The Air Bag Diagnostic Monitor is 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 and Seat Belts for No Communication testing.

- Anti-lock Brake System (ABS) Module

NOTE: The Anti-lock Brake System (ABS) Module is included on this network only if the vehicle is not equipped with traction control.

The Anti-lock Brake System Control Module is 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)

The Generic Electronic Module is plugged into the fuse junction panel. A failed Generic Electronic Module may cause a no communication condition on ISO 9141 communication link. If communication to the generic electronic module fails, refer to the affected sub-system for No Communication testing.

- Remote Anti-theft Personality (RAP)

The Remote Anti-theft Personality Module is located under the instrument panel to the right of the steering column. A failed Remote Anti-theft Personality Module may cause no communication condition on ISO 9141 communication link. If communication to the remote anti-theft personality module fails, refer to Keyless Entry for No Communication testing.