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 driver door module (DDM) monitors the Driver Door Key Switch 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 latch assembly, provides a switched ground for the signal circuit. The DDM communicates the status of the driver door key switch to the BCM via serial data.

Schematic Reference

Door Lock/Indicator Schematics

Connector End View Reference

Vehicle Access 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 switch.
2. Ignition OFF, test for less than 1.0 ohm of resistance between the low reference circuit terminal B and ground.

⇒	If greater than the specified range, test the low reference 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 terminal A for a short to ground. If the circuit tests normal, replace the DDM.

4. Install a 3A fused jumper wire between the signal circuit terminal A 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 DDM.

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

1. Ignition OFF, disconnect the harness connector at the driver door latch assembly.
2. Test for infinite resistance between the signal terminal A and the low reference terminal B with the switch in the open position.

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

3. Test for less than 2.0 ohms of resistance between the signal terminal A and the low reference terminal B with the switch in the closed position.

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

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

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.