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For 1990-2009 cars only
Makes 🢒 Buick 🢒 2009 🢒 Allure 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 Power Door Lock Key Cylinder Switches Inoperative

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

Door Lock Key Switch Unlock Signal

1

1

1

--

Door Lock Key Switch Lock Signal

1

1

1

--

Driver Door Lock Ground

--

1

1

--

1. Key Cylinder Switch Malfunction

Circuit/System Description

The key cylinder lock/unlock feature will unlock or lock all of the doors when the body control module (BCM) receives a Door Lock Key Switch Unlock or Lock signal for greater than 1 second and will unlock or lock all of the doors.

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
  1. Ignition ON, command the Lock All Doors and Unlock All Doors with a scan tool, all doors should perform the LOCK and UNLOCK functions.
    2. ⇒If any door fails to LOCK or UNLOCK, refer to Power Door Locks Malfunction.
  2. Observe the scan tool LF Key Cylinder Lock Switch parameters while the turning and holding the key in the driver door lock cylinder to the left and then to the right, the parameter should change from Idle to Lock and Unlock.

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the driver door lock.
  2. Test for less than 1 ohm between the ground circuit terminal 8 and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool LF Key Cylinder Lock Switch parameter is Idle.
    4. ⇒If not the specified value, test the signal circuit terminal 9 or signal circuit terminal 4 for a short to ground. If the circuits test normal, replace the BCM.
  4. Install a 3A fused jumper wire between the signal circuit terminal 4 and ground, verify the scan tool LF Key Cylinder Lock Switch parameter is Lock.
    5. ⇒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. Install a 3A fused jumper wire between the signal circuit terminal 9 and ground, verify the scan tool LF Key Cylinder Lock Switch parameter is Unlock.
    6. ⇒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.
  6. If all circuits tests normal, test or replace the driver door lock.

Component Testing
  1. Ignition OFF, disconnect the harness connector at the driver door lock.
  2. Test for infinite resistance between the signal terminal 9 and the ground terminal 8 with the switch in the Idle position.
    3. ⇒If not the specified value, replace the driver door lock.
  3. Test for infinite resistance between the signal terminal 4 and the ground terminal 8 with the switch in the Idle position.
    4. ⇒If not the specified value, replace the driver door lock.
  4. Test for less than 2 ohms between the signal terminal 9 and the ground terminal 8 with the switch in the Unlock position.
    5. ⇒If greater than the specified range, replace the driver door lock.
  5. Test for less than 2 ohms between the signal terminal 4 and the ground terminal 8 with the switch in the Lock position.
    6. ⇒If greater than the specified range, replace the driver door lock.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Front Side Door Lock Replacement
    •  Control Module References for BCM replacement, setup and programming