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 B3140 00: Driver Unlock Switch Circuit

DTC B3145 00: Passenger Unlock Switch Circuit

DTC B3150 00: Driver Lock Switch Circuit

DTC B3155 00: Right Front Lock Switch Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Driver Door Lock Switch Lock Signal

B3150 00

1

1

--

Driver Door Lock Switch Unlock Signal

B3140 00

1

1

--

Passenger Door Lock Switch Lock Signal

B3155 00

2

2

--

Passenger Door Lock Switch Unlock Signal

B3145 00

2

2

--

Door Lock Actuator Lock Control

3

3

3

--

Door Lock Actuator Unlock Control

3

3

3

--

Lock PCB Relay Control

B3135 00

3

3

--

Unlock PCB Relay Control

3

B3125 00, B3130 00

3

--

Driver Door Lock Switch Ground

--

1

1

--

I/P Fuse Block Ground

--

3

3

--

Passenger Door Lock Switch Ground

--

2

2

--

1. Driver Door Lock Switch Malfunction

2. Passenger Door Lock Switch Malfunction

3. Door Latch Malfunction

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

B3140 00 or B3150 00

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

B3145 00 or B3155 00

The BCM detects a fault in the passenger door lock switch lock or unlock signal circuits.

Action Taken When the DTC Sets

The driver or passenger 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

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

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

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the appropriate door lock switch.
  2. Ignition ON, verify the scan tool Door Lock Sw parameter is Inactive.
  3. If not the specified value, test the signal circuit terminal D for a short to ground. If the circuit tests normal, replace the BCM.
  4. Verify the scan tool Door Unlock Sw parameter is Inactive.
  5. If not the specified value, test the signal circuit terminal E for a short to ground. If the circuit tests normal, replace the BCM.
  6. Install a 3A fused jumper wire between the signal circuit terminal D and ground. Verify the scan tool Door Lock Sw parameter is Active.
  7. 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.
  8. Install a 3A fused jumper wire between the signal circuit terminal E and ground. Verify the scan tool Door Unlock Sw parameter is Active.
  9. 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.
  10. If all circuits test normal, test or replace the door lock switch.

Component Testing

  1. Ignition OFF, disconnect the harness connector at the appropriate 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.
  3. If less than the specified value, replace the door lock switch.
  4. Test for less than 2 ohms between the signal terminal D and the ground terminal B with the switch in the lock position.
  5. If greater than the specified range, replace the door lock switch.
  6. Test for less than 2 ohms between the signal terminal E and the ground terminal B with the switch in the unlock position.
  7. If greater than the specified range, replace the door lock switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Door Lock and Side Window Switch Replacement - Driver Side
    •  Door Lock and Side Window Switch Replacement - Passenger Side
    •  Control Module References for BCM replacement, programming, and setup