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.

### DTC Descriptors

DTC B3140 00: Driver Unlock Switch Circuit
DTC B3150 00: Driver Lock Switch Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
I/P Fuse Block B+ | 1 | 1 | -- | --
Door Lock Switch Lock Signal | B3150 00 | 2 | 2 | --
Door Lock Switch Unlock Signal | B3140 00 | 2 | 2 | --
All Lock Relay Control | B3135 00 | B3135 00 | 1 | --
Door Latch Assembly Control | 1 | 1 | 1 | --
Driver Unlock Relay Control | B3125 00 | B3125 00 | B3125 00 | --
Passenger Unlock Relay Control | B3130 00 | B3130 00 | B3130 00 | --
Window/Door Lock Switch Ground | -- | 2 | 2 | --
Relay Ground | -- | 1 | 1 | --
1. Door Lock Malfunction 2. Door Lock Switch Malfunction

### Circuit/System Description

The body control module (BCM) supplies and monitors a reference voltage to the door lock/window switch through the door lock switch lock and unlock signal circuits. The door lock/window switch also receives a constant ground source. If a door lock switch is placed in the lock position or unlock position, the reference voltage is taken directly to ground and the BCM detects the voltage drop on the signal circuit.

### Conditions for Running the DTC

The system voltage is 9-16 volts.

### Conditions for Setting the DTC

#### B3140 00

The BCM detects a fault in the unlock switch signal circuit.

#### B3150 00

The BCM detects a fault in the lock switch signal circuit

### Action Taken When the DTC Sets

The power door locks will malfunction.

### Conditions for Clearing the DTC

• | The DTC will be current for as long as the fault is present.

• | When the fault is no longer present, the DTC will become a history DTC.

• | A history DTC will clear after 50 ignition cycles.

### 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, observe the scan tool Central Door Lock Switch and Central Door Unlock Switch parameters while using the door lock/window switch. The parameter should change between Inactive and Active when changing between the commanded states.

### Circuit/System Testing

1. Ignition OFF, disconnect the X2 harness connector at the door lock/window switch.
2. Test for less than 20 Ω between the ground circuit terminal 4 and ground.

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

3. Ignition ON, verify the scan tool Central Door Lock Switch parameter is Inactive.

⇒ | If not the specified value, test the signal circuit terminal 15 for a short to ground. If the circuit tests normal, replace the BCM.

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

⇒ | If not the specified value, test the signal circuit terminal 5 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 15 and ground. Verify the scan tool Central Door 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 5 and ground. Verify the scan tool Central Door 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 door lock/window switch.

### Component Testing

1. Ignition OFF, disconnect the X2 harness connector at the door lock window/switch.
2. Test for infinite resistance between the signal terminals 5 and 15 and the ground terminal 4 with the switch in the open position.

⇒ | If less than the specified value, replace the door lock/window switch.

3. Test for less than 2 Ω between the signal terminal 15 and the ground terminal 4 with the switch in the lock position.

⇒ | If greater than the specified range, replace the door lock/window switch.

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

⇒ | If greater than the specified value, replace the door lock/window switch

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Power Mirror Switch Replacement

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