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Home >> Pontiac >> 2009 >> Vibe Base, 2.4 0, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 22 (Door Lock System & Door Handles) >> Diagnostic Information and Procedures >> Power Door Locks Malfunction >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2009 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.

DDM/FPDM Malfunction

  1. Ignition OFF, disconnect the X1 harness connector at the appropriate door module.
  2. Test for less than 1 ohm between the ground circuit terminal 6 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 4 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or open/high resistance. If the circuit tests normal and the door module fuse is open, replace the door module.
  4. Ignition OFF, connect the X1 harness connector at the door module and disconnect the X2 harness connector at the door latch.
  5. Connect a test lamp between control circuit terminal B and control circuit terminal A.
  6. Ignition ON, command the appropriate front door latch to LOCK and UNLOCK by using the door lock switch. The test lamp should briefly illuminate when commanding the LOCK and UNLOCK states.
    • If the test lamp remains OFF during either of the commands, test for a short to ground or an open/high resistance on either control circuit. If the circuits test normal, replace the door module.
    • If the test lamp remains ON during either of the commands, test for a short to voltage on either control circuit. If the circuits test normal, replace the door module.
  7. If all circuits test normal, test or replace the door latch.

Door Unlock Relay Malfunction

  1. Ignition OFF, disconnect the UNLOCK relay.
  2. Test for less than 1 ohm between the relay switch ground circuit terminal and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp does not illuminate between the relay switch control circuit terminal and ground.
    • If the test lamp illuminates, test the control circuit for a short to voltage.
  4. Verify that a test lamp illuminates between the relay coil B+ circuit terminal and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  5. Verify that a test lamp illuminates between the relay switch B+ circuit terminal and ground.
    • If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  6. Connect a test lamp between the relay coil control circuit terminal and the relay coil B+ circuit terminal.
  7. Command the rear doors to UNLOCK with a scan tool. The test lamp should briefly illuminate when commanding the UNLOCK state.
    • 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. Ignition OFF, connect the UNLOCK relay. Disconnect the X2 harness connector at the rear door latch assembly.
  9. Test for less than 1 ohm between the control circuit terminal A and ground.
    • If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuits test normal, test or replace the UNLOCK relay.
  10. Connect a test lamp between control circuit terminal A and ground.
  11. Ignition ON, command the door latch to UNLOCK with a scan tool. The test lamp should briefly illuminate when commanding the UNLOCK state.
    • 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, test or replace the UNLOCK relay.
  12. If all circuits test normal, test or replace the door latch.

Door Lock Relay Malfunction

  1. Ignition OFF, disconnect the LOCK relay.
  2. Test for less than 1 ohm between the relay switch side ground circuit terminal and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp does not illuminate between the relay switch control circuit terminal and ground.
    • If the test lamp illuminates, test the control circuit for a short to voltage.
  4. Ignition OFF, test for less than 1 ohm between the relay coil ground circuit terminal and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  5. Verify that a test lamp illuminates between the relay switch B+ circuit terminal and ground.
    • If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  6. Connect a test lamp between the relay coil control circuit terminal and the relay coil ground circuit terminal.
  7. Command the rear doors to LOCK with a scan tool. The test lamp should briefly illuminate when commanding the LOCK state.
    • 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.
  8. Ignition OFF, connect the LOCK relay. Disconnect the X2 harness connector at the appropriate door latch.
  9. Test for less than 1 ohm between the control circuit terminal B and ground.
    • If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, test or replace the LOCK relay.
  10. Connect a test lamp between control circuit terminal B and ground.
  11. Ignition ON, command the rear doors to LOCK with a scan tool. The test lamp should briefly illuminate when commanding the LOCK state.
    • 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, test or replace the LOCK relay.
  12. If all circuits test normal, test or replace the door latch.
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