GM Service Manual Online
For 1990-2009 cars only

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 Descriptor

DTC B3125 02: Driver Door Only, Unlock Circuit Short to Ground

DTC B3130 02: All Unlock Circuit Short to Ground

DTC B3135 02: All Door Lock Circuit Short to Ground

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Door Lock Switch Signal

B3150 00

B3150 00

B3150 00

--

Door Unlock Switch Signal

B3140 00, B3145 00

B3140 00, B3145 00

B3140 00, B3145 00

--

Driver Door Unlock Control

B3125 02

1, 2, 3

1, 2, 3

--

Doors Lock Control

B3135 02, 4

1, 2, 3

1, 2, 3

--

Passenger Doors Unlock Control

B3130 02

1, 2, 3

1, 2, 3

--

Doors Dead Lock Control

B3797 02

1, 2, 3

1, 2, 3

--

Door Lock Switch Ground

--

1, 2, 3

1, 2, 3

--

1. Door Lock Malfunction

2. Driver Door Unlock Malfunction

3. Door Unlock Malfunction

4. Fuel Filler Door Release Inoperative

Circuit/System Description

The body control module (BCM) controls the door lock, passenger door unlock and driver door unlock circuits. Voltage is applied to the appropriate circuit when the BCM senses a door lock/unlock switch activation or a keyless entry lock or unlock command.

Conditions for Running the DTC

The system voltage is 9-18 V.

Conditions for Setting the DTC

B3125 02

The BCM detects a short to ground on the driver door unlock control circuit.

B3130 02

The BCM detects a short to ground on the unlock door control circuit.

B3135 02

The BCM detects a short to ground on the door lock 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

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

Circuit/System Verification

Command the driver door and passenger door lock actuators to Lock and Unlock with the scan tool, the doors should perform the Lock and Unlock function.

If any door will not lock, refer to Door Lock Circuit Malfunction.
If any door will not unlock, refer to Door Unlock Circuit Malfunction.
If any door will not lock or unlock, refer to Door Lock/Unlock Circuit Malfunction

Circuit/System Testing

  1. Ignition OFF, disconnect the malfunctioning door latch connector.
  2. Connect a test lamp between the appropriate door lock control circuit and the unlock control circuit.
  3. • Left hand drive: A23D Door Latch Assembly - Driver terminals 2 and 3.
    • Right hand drive: A23D Door Latch Assembly - Driver terminals 7 and 8.
    • Left hand drive: A23P Door Latch Assembly - Passenger terminals 7 and 8.
    • Right hand drive: A23P Door Latch Assembly - Passenger terminals 2 and 3.
    • A23LR Door Latch Assembly - Left Rear terminals 2 and 3.
    • A23RR Door Latch Assembly - Right Rear terminals 7 and 8.
  4. Command the doors to Unlock with a scan tool. The test lamp should briefly illuminate when commanding the Unlock state.
  5. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module (BCM).
    If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K9 Body Control Module (BCM).
  6. If all circuits test normal, test or replace the door latch.

Component Testing

Door Latch Test

  1. Ignition OFF, disconnect the harness connector at the appropriate door lock assembly.
  2. Install a 25 A fused jumper wire between the lock control terminal and 12 V. Momentarily install a jumper wire between the unlock control terminal and ground. The door lock should perform the Lock/ Unlock function.
  3. If the function does not perform as specified, replace the door lock.
  4. Reverse the jumper wires; the appropriate door lock should perform the Unlock/Lock function.
  5. If the function does not perform as specified, replace the door lock.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Relay Replacement
    •  Front Side Door Lock Replacement
    •  Rear Side Door Lock Replacement
    •  Control Module References for BCM replacement, setup and programming