Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

The content theft deterrent (CTD) system is a software based system in which the body control module (BCM) actively monitors certain inputs to determine if unauthorized vehicle access is being attempted. The driver door lock cylinder switch is used as an input to disarm the CTD system. The BCM monitors the Door Key Switch Unlock Signal circuit to determine if the driver door cylinder is being rotated, indicating a vehicle key is being used to unlock the vehicle and the CTD system should be disarmed. The door key cylinder switch, located in the door lock assembly, provides a switched ground for the signal circuit.

Schematic Reference

Theft Deterrent System Schematics

Connector End View Reference

Theft Deterrent System Connector End Views

Description and Operation

Content Theft Deterrent (CTD) Description and Operation

Electrical Information Reference

Scan Tool Reference

Ignition ON, verify the scan tool Door Key Cyl. Unlock Switch parameter cycles between Idle and Unlock while turning the driver door lock cylinder with the vehicle key.

1. Ignition OFF, disconnect the harness connector at the driver door lock assembly.
2. Test for less than 1.0 ohm of resistance between the ground circuit terminal 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 Idle.

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

4. Install a 3-A fused jumper wire between the signal circuit terminal and ground. Verify the scan tool Door Key Cyl. Unlock 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.

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

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

⇒	If not the specified value, replace the door lock assembly.

3. Test for less than 2.0 ohms of resistance between the signal circuit terminal and the ground circuit terminal with the switch in the closed position.

⇒	If greater than the specified range, replace the door lock assembly.

4. Test for infinite resistance between each terminal and the door lock assembly housing/case.

⇒	If not the specified value, replace the door lock assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.