GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2006 🢒 LaCrosse 🢒 Body 🢒 Body Rear End 🢒 Trunk Release 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

Trunk Release Control Circuit

1

1

1

-

Door Lock Switch Unlock Signal Circuit

2

2

2

-

Rear Compartment Lid Latch Ground

-

1

1

-

1. Trunk release is inoperative from both the switch and keyless entry transmitter

2. Trunk release is inoperative only from switch

Circuit/System Description

The rear compartment lid can be released by holding either front power door lock switch to the unlock position for a minimum of 2 seconds or by pressing the rear compartment release button on the key fob. The transaxle must be in the PARK position for the rear compartment to release. When the rear compartment lid release is commanded, voltage is applied to the rear compartment lid release actuator from the BCM, thus opening the rear compartment.

Reference Information

Schematic Reference

Body Rear End Schematics

Connector End View Reference

Body Rear End Connector End Views

Description and Operation

Luggage Compartment Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions
    •  Scan Tool Output Controls

Circuit/System Verification
  1. Ignition ON, observe the scan tool LF Door Lock Switch parameter while using driver door lock switch. The parameter should change from Idle to Lock and Unlock.
    2. ⇒If the parameters do not change, refer to Power Door Lock Inoperative - Driver Door .
  2. Command the trunk release with a scan tool, the rear compartment lid latch should release the trunk lid.

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the rear compartment lid latch.
  2. Test for less than 1 ohm between the ground circuit terminal 3 and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the control circuit terminal 4 and the ground circuit terminal 3.
  4. Command the trunk release ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    5. ⇒If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
    ⇒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.
  5. If all circuits test normal, test or replace the rear compartment lid latch

Component Testing
  1. Ignition OFF, disconnect the harness connector at the rear compartment lid latch.
  2. Install a 7.5-amp fused jumper wire between the control terminal 4 and 12 volts. Install a jumper wire between the ground terminal 3 and ground. Verify the rear compartment lid latch activates.
    3. ⇒If the latch does not perform as specified, replace the rear compartment lid latch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Rear Compartment Lid Latch Replacement
    •  Control Module References for BCM replacement, setup, and programming