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

Schematic Reference

Door Lock/Indicator Schematics

Connector End View Reference

Vehicle Access Connector End Views

Description and Operation

Power Door Locks Description and Operation

Electrical Information Reference

Scan Tool Reference

Ignition OFF, insert the key into the driver door lock cylinder, turn the key clockwise and hold for greater than 1 second and turn the key counterclockwise and hold for greater than 1 second. Observe the scan tool LF Key Cylinder Lock Switch parameters, the reading should change between Lock and Unlock.

1. Ignition OFF, disconnect the harness connector at the Driver Door Key Switch.
2. Ignition OFF, test for less than 1.0 ohm of resistance between the ground circuit terminal C and ground.

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

3. Ignition ON, verify the scan tool LF Key Cylinder Lock Switch parameter is Idle.

⇒	If not the specified value, test the signal circuit terminal A or D for a short to ground. If the circuits test normal, replace the BCM.

4. Install a 3-amp fused jumper wire between the signal circuit terminal A and ground, verify the scan tool LF Key Cylinder Lock Switch parameter is Lock.

⇒	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. Install a 3-amp fused jumper wire between the signal circuit terminal D and ground, verify the scan tool LF Key Cylinder Lock Switch parameter is Unlock.

⇒	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

6. If all circuits tests normal, test or replace the Driver Door Key Switch.

1. Ignition OFF, disconnect the harness connector at the Driver Door Key Switch.
2. Test for infinite resistance between the signal terminal A and the ground circuit terminal C with the switch in the open position.

⇒	If not the specified value, replace the Driver Door Key Switch.

3. Test for infinite resistance between the signal terminal D and the ground circuit terminal C with the switch in the open position.

⇒	If not the specified value, replace the Driver Door Key Switch.

4. Test for less than 2.0 ohms between the signal terminal D and the ground circuit terminal C with the switch in the Unlock position.

⇒	If greater than the specified range, replace the Driver Door Key Switch.

5. Test for less than 2.0 ohms between the signal terminal A and the ground circuit terminal C with the switch in the Lock position.

⇒	If greater than the specified range, replace the Driver Door Key Switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.