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Home >> Chevrolet >> 2006 >> Cobalt LTZ >> Repair and Diagnosis >> External Pages >> Different car >> Section 729 (Power Door Lock System And Release Systems) >> Diagnostic Information and Procedures >> Power Door Locks Malfunction >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2008 Pontiac G5 and 2008 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.

Door Lock Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the driver and passenger door lock switches.
  2. Test for less than 1 ohm between the ground circuit terminal A and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Door Lock Switch parameter is Idle.
    • If not the specified value, test the signal circuit terminal C for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3A fused jumper wire between the signal circuit terminal C and ground. Verify the scan tool Door Lock Switch parameter is Lock.
    • 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.
  5. Ignition OFF, connect the harness connector at the driver door lock switch.
  6. Ignition ON, observe the scan tool Door Lock Switch parameter while using the driver door lock switch. The parameter should change from Idle to Lock and Unlock.
    • If the parameter does not change, test or replace the driver door lock switch.
  7. If all circuits test normal, test or replace the passenger door lock switch.

Door Lock Malfunction

  1. Ignition OFF, disconnect the X4 harness connector at the BCM.
  2. Test for less than 1 ohm between the ground circuit terminal E12 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Connect the X4 harness connector at the BCM and disconnect the harness connector at the appropriate door latch.
  4. Test for less than 1 ohm between the control circuit terminal 2 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, replace the BCM.
  5. Test for less than 1 ohm between the control circuit terminal 3 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, replace the BCM.
  6. Connect a test lamp between the control circuit terminal 2 and control circuit terminal 3.
  7. Ignition ON, command the door latch to LOCK and UNLOCK with a scan tool. The test lamp should briefly illuminate when commanding the LOCK and UNLOCK states.
    • If the test lamp is always OFF, test either control circuit for a short to ground. If the circuit tests normal, replace the BCM.
  8. If all circuits test normal, test or replace the door latch.
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