Power Door Lock Key Cylinder Switches Inoperative

Power Door Lock Key Cylinder Switches Inoperative

Diagnostic Instructions

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

Diagnostic Fault Information





Circuit/System Description

The key cylinder unlock feature will unlock all of the doors when the body control module (BCM) receives a Door Lock Key Switch Unlock signal for greater than 1 second and will unlock all of the doors.

Reference Information
Schematic Reference

Door Lock/Indicator Schematics (Door Lock/Indicator Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Power Door Locks Description and Operation (Description and Operation)
Electrical Information Reference

* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Circuit Testing (Circuit Testing)
* Wiring Repairs (Wiring Repairs)
* Connector Repairs (Connector Repairs)

Scan Tool Reference

Programming and Relearning (Programming and Relearning) for scan tool information

Circuit/System Verification

Ignition ON, insert the key into the driver door lock cylinder, turn the key the unlock position and hold for greater than 1 second while observing the scan tool Door Key Cyl Unlock Switch parameter. The parameter should change between Active and Inactive.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the driver door lock.
2. Test for less than 1 ohm between the ground circuit terminal 8 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify the scan tool Door Key Cyl Unlock Switch parameter is Inactive.

• If not the specified value, test the signal circuit terminal 9 for a short to ground. If the circuit tests normal, replace the BCM.

4. Install a 3-amp fused jumper wire between the signal circuit terminal 9 and ground, verify the scan tool Door Key Cyl Unlock Switch parameter is Active.

• If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

5. If all circuits test normal, test or replace the driver door lock.

Component Testing

1. Ignition OFF, disconnect the harness connector at the driver door lock.
2. Test for infinite resistance between the signal terminal 9 and the ground terminal 8 with the switch in the open position.

• If not the specified value, replace the driver door lock.

3. Test for less than 2 ohms between the signal terminal 9 and the ground terminal 8 with the switch in the Unlock position.

• If greater than the specified range, replace the driver door lock.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Door Lock Cylinder Replacement (Impala) (Removal and Replacement)
* Programming and Relearning (Programming and Relearning) for BCM replacement, setup, and programming