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
--- | --- | --- | --- | ---
Driver Door Key Switch Signal | 1 | 1 | 1 | --
Right Front Door Latch Ground | -- | 1 | 1 | --
1. Key Cylinder Switch Inoperative

### Circuit/System Description

The body control module (BCM) monitors the voltage level of the key switch lock and unlock signal circuits. When the key is inserted into the right front door key cylinder and turned and held to the Unlock or Lock position, a switch within the right front door latch closes causing the voltage to drop within the appropriate key switch signal circuit. When the voltage drop time exceeds 2 seconds, the BCM will command all the doors to unlock or lock.

### Reference Information

#### Schematic Reference

Door Lock/Indicator Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Power Door Locks 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, insert the key into the right front door lock cylinder, turn the key to the LOCK position and then to the UNLOCK positon while observing the scan tool Door Key Cylinder Lock Switch and Door Key Cylinder Unlock Switch parameters. The parameters should change between Inactive and Active.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the right front door latch.
2. Test for less than 1 Ω between the ground circuit terminal 3 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 Cylinder Lock Switch parameter is Inactive.

⇒ | If not the specified value, test the signal circuit terminal 9 for a short to ground. If the circuit tests normal, replace the BCM.

4. Verify the scan tool Door Key Cylinder Unlock Switch parameter is Inactive.

⇒ | If not the specified value, test the signal circuit terminal 4 for a short to ground. If the circuit tests normal, replace the BCM.

5. Install a 3A fused jumper wire between the signal circuit terminal 9 and ground, verify the scan tool Door Key Cylinder Lock Switch parameter is Active.

⇒ | 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. Install a 3A fused jumper wire between the signal circuit terminal 4 and ground, verify the scan tool Door Key Cylinder Unlock Switch parameter is Active.

⇒ | 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.

7. If all circuits test normal, test or replace the right front door latch.

### Component Testing

1. Ignition OFF, disconnect the harness connector at the right front door latch.
2. Test for infinite resistance between the signal terminal 4 and the ground terminal 3 with the switch in the open position.

⇒ | If not the specified value, replace the right front door latch.

3. Test for infinite resistance between the signal terminal 9 and the ground terminal 3 with the switch in the open position.

⇒ | If not the specified value, replace the right front door latch.

4. Test for less than 2 Ω between the signal terminal 9 and the ground terminal 3 with the switch in the Lock position.

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

5. Test for less than 2 Ω between the signal terminal 4 and the ground terminal 3 with the switch in the Unlock position.

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

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Front Side Door Latch Replacement

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