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.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Deadbolt Lock Control

1

1

1

--

Deadbolt Unlock Control

1

1

1

--

1. Power Door Locks Deadbolt Malfunction

Circuit/System Description

Export vehicles may be equipped with the deadbolt feature, which includes a reversible deadbolt motor contained within each door latch assembly. Each deadbolt motor is wired to their respective door modules through 2 circuits, the deadbolt lock control circuit and the deadbolt unlock control circuit. To deadbolt a door, the body control module (BCM) locks the door by momentarily applying voltage to the door latch motor control circuit. To complete the deadbolting, the door module momentarily applies voltage to the deadbolt lock control circuit and ground to the deadbolt unlock control circuit. If the content theft feature is armed at the same time, the interior door lock switches will not operate the locks.

To undeadbolt the door, the door module reverses the polarity, applying battery voltage to the deadbolt unlock control circuit, and ground to the deadbolt lock control circuit.

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, command the Door Deadbolt Lock/Unlock ON and OFF with a scan tool for each door. The deadbolts from each door should perform the LOCK and UNLOCK functions.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the appropriate door latch.
  2. Connect a test lamp between control circuit terminals listed below:
  3. • Driver door latch terminal 1 and terminal 2 (RHD)
    • Driver door latch terminal 6 and terminal 7 (LHD)
    • Passenger door latch terminal 6 and terminal 7 (RHD)
    • Passenger door latch terminal 1 and terminal 2 (LHD)
    • Left rear door latch terminal 1 and terminal 2
    • Right rear door latch terminal 4 and terminal 5
  4. Command the Door Deadbolt Lock/Unlock ON and OFF with a scan tool with a scan tool. The test lamp should illuminate when commanding the LOCK and UNLOCK states.
  5. If the test lamp remains OFF during either of the commands, test either control circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the door module.
    If the test lamp is always ON, test either control circuit for a short to voltage. If the circuits test normal, replace the door module.
  6. If all circuits test normal, test or replace the door latch.

Component Testing

Door Latch Assembly

  1. Ignition OFF, disconnect the harness connector at the appropriate door latch.
  2. Install a 15A fused jumper wire between one of the control terminals and 12V. Momentarily install a jumper wire between the other control terminal and ground. Reverse the jumper wires at least two times, the deadbolt should perform the LOCK/ UNLOCK functions.
  3. If it does not perform as specified, replace the door latch

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Front Side Door Lock Replacement
    •  Rear Door Lock Replacement
    •  Control Module References for DDM, PDM, LRDM, RRDM replacement, setup, and programming