GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

This feature prevents the locking of the driver door if the ignition key is left in the ignition lock cylinder. If a lock function occurs from any door lock switch and the body control module (BCM) senses an active state on either the left front door latch signal, secondary door latch switch signal and/or the liftgate ajar switch signal circuits and the key in ignition switch signal circuit is in the YES state, the BCM, driver door module and passenger door module will lock the doors and then the driver door module will unlock the driver door.

Reference Information

Schematic Reference

Door Lock/Indicator Schematics

Connector End View Reference

    •  Vehicle Access Connector End Views
    •  Data Communication Connector End Views

Description and Operation

Power Door Locks Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions
    •  Scan Tool Output Controls

Circuit/System Verification

With the ignition OFF, the key in the ignition and the driver window down, exit the vehicle, lock and close all doors. The driver door should unlock.

Circuit/System Testing

  1. Command the doors to LOCK and UNLOCK by pressing the door lock switch.
  2. If one or more doors fail to LOCK and UNLOCK, refer to Power Door Locks Inoperative.
  3. Ignition OFF, with a scan tool, observe the Key in Ignition Status, the parameter should be Key In.
  4. If the reading is Key Out, refer to Chime Inoperative.
  5. With a scan tool, observe each of the Door Ajar Switch parameters while opening and closing each door, the reading should change between Door Closed and Ajar.
  6. If the reading on any door continuously reads Ajar, refer to Door Ajar Indicator Malfunction.
  7. If all circuits are normal, replace the BCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for BCM replacement, setup and programming