B3140

DTC B3140 or B3150

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 02
- Unlock Switch Circuit Short to Ground

DTC B3150 02
- Lock Switch Circuit Short to Ground




Diagnostic Fault Information






Circuit/System Description

The front passenger door lock switch is wired to the passenger door module (PDM). The lock switch receives a constant ground source. There are 2 signal circuits, one for lock signal, and one for unlock signal. When the switch is activated for a lock or unlock function, the normally open switch contacts for that function are closed and provide a switched ground signal to the PDM.


The driver door lock switch is wired to the driver door switch assembly (DDSA). The lock switch receives a constant ground source. There are 2 signal circuits, one for lock signal, and one for unlock signal. When the switch is activated for a lock or unlock function, the normally open switch contacts for that function are closed and provide a switched ground signal to the DDSA. These switch activations are detected and processed by the DDSA and then communicated to the driver door module (DDM) via a GMLAN message.


Conditions for Running the DTC

* The DDSA must be powered.
* DTC B1325 Battery Voltage Out of Range, must not be current.



Conditions for Setting the DTC

The DDSA detects that either the Lock or Unlock switch is closed for more than 30 continuous seconds.


Action Taken When the DTC Sets

The DDSA and PDM ignores inputs from the Lock/Unlock switch.


Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.
* You issue a scan tool CLEAR DTCs command.
* A history DTC will clear once 40 consecutive malfunction-free ignition cycles have occurred.



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 Latch Description and Operation (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)


Circuit/System Verification

1. Ignition ON, observe the scan tool door lock switch parameter located in the driver door switch data display menu while activating the driver door lock switch to the LOCK and UNLOCK positions. The reading should toggle between LOCK, UNLOCK, and IDLE as the switch is activated.

• If the reading does not change between the commanded states, refer to Door Lock Switch Malfunction - Driver.

2. Ignition ON, observe the scan tool door lock switch parameter located in the passenger door module (PDM) data display menu while activating the passenger door lock switch to the LOCK and UNLOCK positions. The reading should toggle between LOCK, UNLOCK, and IDLE as the switch is activated.

• If the reading does not change between the commanded states, refer to Door Lock Switch Malfunction - Passenger.




Circuit/System Testing


Door Lock Switch Malfunction - Driver
1. Ignition OFF, disconnect the harness connector at the driver door lock switch.
2. Ignition OFF, scan tool OFF, test for less than 10.0 ohms between the ground circuit terminal C 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 lock switch parameter located in the driver door switch menu displays IDLE.

• If not the specified value, test the appropriate signal circuit for a short to ground. If the circuit tests normal, replace the DDSA.

4. Install a 3A fused jumper wire between the signal circuit terminal D and ground. Verify the scan tool door lock switch parameter displays LOCK.

• If not the specified value, test the signal circuit terminal D for a short to voltage or an open/high resistance. If the circuit tests normal, replace the DDSA.

5. Install a 3A fused jumper wire between the signal circuit terminal E and ground. Verify the scan tool door lock switch parameter displays UNLOCK.

• If not the specified value, test the signal circuit terminal E for a short to voltage or an open/high resistance. If the circuit tests normal, replace the DDSA.

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



Door Lock Switch Malfunction - Passenger
1. Ignition OFF, disconnect the harness connector at the passenger door lock switch.
2. Ignition OFF, scan tool OFF, test for less than 10.0 ohms between the ground circuit terminal 1 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 lock switch parameter located in the passenger door module (PDM) menu displays IDLE.

• If not the specified value, test the appropriate signal circuit for a short to ground. If the circuit tests normal, replace the front PDM.

4. Install a 3A fused jumper wire between the signal circuit terminal D and ground. Verify the scan tool door lock switch parameter displays LOCK.

• If not the specified value, test the signal circuit terminal D for a short to voltage or an open/high resistance. If the circuit tests normal, replace the front PDM.

5. Install a 3A fused jumper wire between the signal circuit terminal E and ground. Verify the scan tool door lock switch parameter displays UNLOCK.

• If not the specified value, test the signal circuit terminal E for a short to voltage or an open/high resistance. If the circuit tests normal, replace the front PDM.

6. If all circuits test normal, test or replace the passenger door lock switch.



Repair Instructions

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

* Door Lock Switch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for DDSA or PDM replacement, setup, and programming