For 1990-2009 cars

### DTC Descriptor

DTC B3140 00: Driver Unlock Switch Circuit

### Diagnostic Fault Information

Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

### Circuit/System Description

When the door lock switch is placed in to the UNLOCK position, ground is applied through the switch to the body control module (BCM). The BCM then applies a ground through the door unlock relay control circuit to the coil side of the unlock relay in the underhood electrical centre. The relay then engages and applies voltage to all the door lock assemblies.

### Conditions for Running the DTC

The ignition is ON.

### Conditions for Setting the DTC

The BCM receives a ground signal on the door unlock relay control circuit

### Action Taken When the DTC Sets

The BCM ceases attempt to unlock the doors.

### Conditions for Clearing the DTC

The BCM clears this code from current when the fault is removed from the system.

### Reference Information

#### Schematic Reference

Door Lock/Indicator Schematics .

#### Connector End View Reference

Vehicle Access Component Views

#### Electrical Information Reference

• | Circuit Testing .

• | Connector Repairs .

• | Testing for Intermittent Conditions and Poor Connections .

• | Wiring Repairs .

#### Scan Tool Reference

Control Module References

### Circuit/System Verification

Ignition ON, place the driver door lock switch to the UNLOCK position. The driver door should unlock.

### Circuit/System Testing

1. Disconnect the unlock relay in the underhood electrical centre. Verify the DTC resets.

⇒ | If the DTC does not reset, replace the relay.

2. Disconnect the underhood fuse centre electrical connector. Verify the DTC resets.

⇒ | If the DTC does not reset, replace the underhood fuse centre.

3. Test for a short to ground/voltage or open/high resistance in the door unlock relay control circuit.

⇒ | If the circuit tests normal, replace the BCM.

### Repair Instructions

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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

• | Underhood Electrical Center or Junction Block Replacement .