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 Descriptors

DTC B3130 00: All Door Unlock Circuit

DTC B3135 00: All Door Lock Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

I/P Fuse Block B+

3, 4

3, 4

--

--

Driver Door Latch Control

1

1

1

--

Passenger Door Latch Control

2

2

2

--

Lock/Unlock PCB Relay Control

B3130 00, B3135 00

3, 4

3, 4

--

Rear Door Latch Control

3, 4

3, 4

3, 4

--

I/P Fuse Block Ground

--

3, 4

3, 4

--

1. Driver Door Latch Malfunction

2. Passenger Door Latch Malfunction

3. Rear Door Unlock Inoperative

4. Rear Door Lock Inoperative

Circuit/System Description

The LOCK/UNLOCK relay is controlled by the body control module (BCM) by providing voltage to one side of the relay or providing a ground to the other side of the relay. During lock or unlock operation, battery voltage will be supplied to the lock actuators through the energized side of the relay and grounded through the de-energized side of the relay.

Conditions for Running the DTC

The system voltage must be between 9-16 volts.

Conditions for Setting the DTC

B3130 00

The BCM detects a fault on the REAR DOOR LOCK/UNLOCK relay control circuit while commanding the rear doors to unlock.

B3135 00

The BCM detects a fault on the REAR DOOR LOCK/UNLOCK relay control circuit while commanding the rear doors to lock.

Action Taken When the DTC Sets

The rear power door locks 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 become 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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Command the Lock Rear Doors and Unlock Rear Doors with a scan tool, the rear doors should perform the LOCK and UNLOCK function.

Circuit/System Testing

  1. Ignition OFF, disconnect the X3 harness connector at the I/P fuse block.
  2. Connect a test lamp between the control circuit terminal A2 and ground.
  3. Ignition ON, command the Lock Rear Doors with a scan tool. The test lamp should briefly illuminate during the LOCK command.
  4. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
    If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  5. Connect a test lamp between the control circuit terminal A3 and B+.
  6. Command the Unlock Rear Doors with a scan tool. The test lamp should briefly illuminate during the UNLOCK command..
  7. 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 BCM.
    If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.
  8. If all circuits test normal, replace the I/P fuse block.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Instrument Panel Electrical Center or Junction Block Replacement - Left Side
    •  Control Module References for BCM replacement, setup and programming