For 1990-2009 cars

### Diagnostic Instructions

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

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Door Lock Key Switch Unlock Signal | 1 | 1 | 1 | --
Ground | -- | 1 | 1 | --
1. Content Theft Deterrent Will Not Disarm Using Door Key

### Circuit/System Description

The content theft deterrent (CTD) system is a software based system in which the rear electrical center (REC) 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 REC monitors the door lock 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 driver door latch assembly, provides a switched ground for the signal circuit.

### Reference Information

#### Schematic Reference

Theft Deterrent System Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Content Theft Deterrent (CTD) Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

Ignition ON, verify the scan tool LF Key Cylinder Lock Switch parameter cycles between Idle and Unlock while turning the driver door lock cylinder to the unlock position with the vehicle key.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the driver door latch assembly.
2. Ignition OFF, test for less than 10 ohms 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 LF Key Cylinder Lock Switch parameter is Idle.

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

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

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

### Component Testing

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

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

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Front Side Door Lock Replacement

• | Control Module References for REC replacement, setup, and programming