Power Door Locks Inoperative

Power Door Locks Inoperative

Diagnostic Instructions

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

Diagnostic Fault Information





Circuit/System Description

The DOOR LKS fuse supplies battery positive voltage to the body control module (BCM) for the power door lock system. The power door locks are controlled by the Keyless Entry Transmitter only. There are no separate driver or passenger door lock switches.

The BCM, upon receipt of a lock or unlock signal from the remote control door lock receiver (RCDLR), will switch the appropriate door lock/unlock relay coil control circuit to ground causing the appropriate door lock/unlock relay to energize. With the relay energized, voltage is applied to the door lock actuator control circuit causing the door to either lock, or unlock depending on what command was received from the RCDLR. When a power door lock/unlock relay is not energized, the switch contacts are normally grounded through the BCM which provides ground to the appropriate door lock actuator for the lock/unlock function being performed. The power door lock/unlock functions are performed by reversing the flow of voltage through the door lock actuator control circuits. The BCM has three internal drivers for the power door lock system. Driver door unlock, passenger door unlock and all door lock. This is done to isolate the driver door lock actuator so it can be unlocked separately from the passenger door. For additional information concerning keyless entry, refer to Keyless Entry System Description and Operation.

Circuit/System Testing

Door Locks Inoperative - One
1. Ignition OFF, disconnect the inoperative door lock actuator harness connector.
2. Connect a test lamp between the inoperative door lock actuator lock and unlock control circuits at the inoperative door lock actuator harness connector.
3. Ignition ON, install a scan tool and perform the door lock and unlock test located in the BCM special functions menu. The test lamp should illuminate as the lock and unlock test is performed.

• If the test lamp does not illuminate, repair the door lock actuator lock and unlock control circuits for an open/high resistance. If the circuits test normal, replace the BCM.

4. If all circuits test normal, test or replace the door lock actuator.

Door Locks Inoperative - All
1. Ignition ON, install a scan tool and perform the door lock and unlock test located in the BCM special functions menu. Both doors should lock and unlock as the test is performed.

• If both doors do not lock and unlock, replace the BCM.

Repair Instructions

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

* Front Side Door Lock Replacement
* Control Module References for BCM replacement, setup, and programming Programming and Relearning