B3140

DTC B3140

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



DTC Descriptors
DTC B3140 00
- Driver Unlock Switch Circuit




Diagnostic Fault Information






Circuit/System Description

The body control module (BCM) supplies and monitors a reference voltage to the door lock switch through the door lock switch lock/unlock signal circuit. The door lock 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 must be between 9-16 volts.


Conditions for Setting the DTC

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


Action Taken When the DTC Sets

The driver door lock switch 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 be a history DTC.
* A history DTC will clear after 50 ignition cycles.



Reference Information
Schematic Reference

Door Lock/Indicator Schematics (Door Lock/Indicator Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Power Door Locks Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Verification

Ignition ON, observe the scan tool Driver Door Unlock Sw parameter while using the driver door lock switch. The parameter should change between Inactive and Active.


Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the driver door lock switch.
2. Ignition ON, verify the scan tool Door Unlock Sw parameter is Inactive.

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

3. Install a 3A fused jumper wire between the signal circuit terminal E and ground. Verify the scan tool Door Unlock Sw 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.

4. If all circuits test normal, test or replace the driver door lock switch.



Component Testing

1. Ignition OFF, disconnect the harness connector at the driver door lock switch.
2. Test for infinite resistance between the signal terminals D and E and the ground terminal B with the switch in the at rest position.

• If less than the specified value, replace the driver door lock switch.

3. Test for less than 2 ohms between the signal terminal D and the ground terminal B with the switch in the lock position.

• If greater than the specified range, replace the driver door lock switch.

4. Test for less than 2 ohms between the signal terminal E and the ground terminal B with the switch in the unlock position.

• If greater than the specified range, replace the driver door lock switch.




Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Door Lock and Side Window Switch Replacement - Driver Side (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming