FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.
Home >> Buick >> 2012 >> LaCrosse AWD V6-3.6L >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> B Code Charts >> B3125

B3125




DTC B3125, B3130, or B3135

Diagnostic Instructions

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

DTC Descriptors
DTC B3125 02
- Driver Door Only Unlock Circuit Short to Ground

DTC B3130 02
- All Doors Unlock Circuit Short to Ground

DTC B3135 02
- All Doors Lock Circuit Short to Ground

Diagnostic Fault Information






Circuit/System Description

The body control module (BCM) controls the driver and passenger door latches. When the BCM receives a driver door unlock, passenger door unlock or all door lock command, it will provide voltage to the appropriate door lock circuits and ground to the opposite door lock circuits causing the actuator to perform the lock or unlock function.

Conditions for Running the DTC

Ignition ON.

Conditions for Setting the DTC

B3125 02, B3130 02 and B3135 02
* A short to ground or an open/high resistance in the BCM B+ circuit.
* The BCM detects a short to ground on a door latch control circuit.

Action Taken When the DTC Sets

The power door locks will be inoperative.

Conditions for Clearing the DTC

* This 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 End Views By Name
Description and Operation

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

* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

Command the doors to LOCK and UNLOCK by using the central door lock switch, the doors should LOCK and UNLOCK when changing between the commanded states.

If the driver door does not LOCK or UNLOCK, refer to Driver Door Lock Malfunction.

If one or more passenger doors do not LOCK or UNLOCK, refer to Passenger Door Lock Malfunction.

If all doors do not LOCK and UNLOCK, refer to All Door Locks Inoperative.

Circuit/System Testing

Driver Door Lock Malfunction
1. Ignition OFF, disconnect the harness connector at the A23D door latch assembly-driver.
2. Connect a test lamp between the control circuit terminal 2 and the control circuit terminal 3
3. Command the driver door latch to LOCK and UNLOCK with a scan tool, the test lamp should illuminate when commanding the LOCK and UNLOCK states.

• If the test lamp is OFF during either of the LOCK and UNLOCK commands, test either control circuit for an open/high resistance. If the circuits test normal, replace the K9 body control module.

• If the test lamp always ON , test either control circuit for a short to voltage. If the circuits test normal, replace the K9 body control module.

4. If all circuits test normal, test or replace the A23D door latch assembly-driver

Passenger Door Lock Malfunction
1. Ignition OFF, disconnect the harness connector at the appropriate passenger or rear A23 door latch assembly.
2. Connect a test lamp between the control circuit terminals listed below:

* A23P door latch assembly-passenger control circuit terminal 7 and control circuit terminal 8
* A23RR door latch assembly-right rear control circuit terminal 7 and control circuit terminal 8
* A23LR door latch assembly-left rear control circuit terminal 2 and control circuit terminal 3

3. Command the door to LOCK and UNLOCK with a scan tool, the test lamp should illuminate when commanding the LOCK and UNLOCK states.

• If the test lamp is OFF during either of the LOCK and UNLOCK commands, test either control circuit for an open/high resistance. If the circuits test normal, replace the K9 body control module.
• If the test lamp always ON , test either control circuit for a short to voltage. If the circuits test normal, replace the K9 body control module.

4. If all circuits test normal, test or replace the A23 door latch assembly

All Door Locks Inoperative
1. Ignition OFF, disconnect the X2 harness connector at the K9 body control module.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 4 and ground.

• If the test lamp does not illuminate and the B+ fuse is normal, test the B+ circuit for an open/high resistance.

• If the test lamp does not illuminate and the circuit fuse is open, test the B+ circuit for a short to ground. If the circuit tests normal, disconnect each of the A23 door latch assemblies and test each control circuit for a short to ground.

3. Ignition OFF, connect the X2 harness connector at the K9 body control module.
4. Disconnect the harness connector at the A23D door latch assembly-driver, the A23P door latch assembly-passenger, the A23LR door latch assembly-left rear and the A23RR door latch assembly-right rear.

Note: Leaving the DMM connected between a control circuit and ground for greater than 20 seconds will cause the K9 body control module to interpret the test as a system fault and will cause the voltage on the control circuit to drop to 0 V. If the voltage drops to 0 V, operate the door locks using the central door lock switch to restore the voltage for testing.

5. Test for greater than 7 V between the control circuit terminal listed below and ground:

* Control circuit terminal 3 at the A23D door latch assembly-driver
* Control circuit terminal 2 at the A23D door latch assembly-driver
* Control circuit terminal 8 at the A23P door latch assembly-passenger

• If less than the specified range, test the control circuit for a short to ground. If the circuit tests normal, replace the K9 body control module.

6. Test for infinite resistance between the control circuit terminal 7 and ground at the A23LR door latch assembly-left rear.

• If not the specified value, test the control circuit for a short to ground.

7. Verify the DTC does not set after connecting each A23 door latch assembly harness connector, one at a time.

• If the DTC sets, test or replace the A23 door latch assembly that was connected immediately before the DTC set.

8. If all circuits test normal, replace the K9 body control module.

Component Testing

Door Latch Test
1. Ignition OFF, disconnect the harness connector at the appropriate A23 door latch assembly.
2. Install a 15 A fused jumper wire between one of the control terminals and 12 V. Momentarily install a jumper wire between the other control terminal and ground. Reverse the jumper wires at least two times, the A23 door latch assembly should perform the LOCK and UNLOCK functions.

• If it does not perform as specified, replace the appropriate A23 door latch assembly

Repair Instructions

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

* Fuse Block Replacement Fuse Block Replacement
* Front Side Door Lock Replacement Front Side Door Lock Replacement
* Rear Side Door Lock Replacement Rear Side Door Lock Replacement
* Control Module References Control Module References for BCM replacement, setup and programming

pro multis Credits:Operation CHARM About Operation CHARM