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.

DTC Descriptors

DTC B3265 01: Trunk Release Output Circuit Short to Battery

DTC B3265 06: Trunk Release Output Circuit Short to Ground or Open

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Trunk Release Relay Control circuit

1

1

1

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1. Trunk Release System Malfunction

Circuit/System Description

The body control module (BCM) provides a low side drive output that controls the trunk relay. The BCM monitors the voltage level on the trunk release relay control circuit to determine when a failure has occurred. The voltage level on this circuit should be high while the trunk relay is not energized, that is; the trunk release feature has not been activated. Voltage will be near 0 volt when the relay is energized. When the BCM receives a trunk release signal from a switch or keyless entry transmitter, it responds by applying ground to the trunk release relay control circuit, which energizes the trunk relay.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The following conditions exist for more than 1 second:

B3265 01

The BCM detects a short to battery in the trunk release relay control circuit when the output is active.

B3265 06

The BCM detects a short to ground or an open in the trunk release relay control circuit when the output is inactive.

Action Taken When the DTC Sets

The BCM disables the trunk release relay control until the next ignition cycle.

Conditions for Clearing the DTC

    • The current DTC clears when the malfunction is no longer present.
    • The history DTC will clear after 100 consecutive fault-free ignition cycles have occurred.

Reference Information

Schematic Reference

Release Systems Schematics

Connector End View Reference

Vehicle Access Connector End Views

Electrical Information Reference

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

Scan Tool Reference

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

Diagnostic Aids

DTC B3265 06 will also set anytime the 10-amp TRUNK fuse is open. Besides a short to ground on the relay coil voltage supply circuit or the relay switch voltage supply circuit, a short to ground on the rear compartment lid release actuator output circuit can cause the fuse to open.

Circuit/System Verification

Ignition ON, press and hold the liftgate touch pad, observe the Liftgate Release Switch parameter in the scan tool. The scan tool Liftgate Release Switch parameter should display active momentarily. The trunk lid should release.

Circuit/System Testing

  1. Ignition OFF, disconnect the trunk relay from the rear fuse block.
  2. Ignition ON, verify that the rear compartment lid latch is deactivated.
  3. If the rear compartment lid latch is still activated, repair the relay switch control circuit (56) for a short to voltage.
  4. Verify that a test lamp illuminates between the relay coil voltage supply circuit and ground.
  5. If the test lamp does not illuminate, repair the voltage supply circuit for a short to ground or an open/high resistance. If the voltage supply circuit fuse is open, test the relay switch control circuit (56) for a short to ground. If all circuit tests normal, test or replace the trunk relay.
  6. Verify that a test lamp illuminates between the relay switch voltage supply circuit and ground.
  7. If the test lamp does not illuminate, repair the relay switch voltage supply circuit for a short to ground or an open/high resistance.
  8. Disconnect the harness connector of the rear compartment lid latch.
  9. Test for less than 1.0 ohm of resistance between the lid latch ground circuit and ground.
  10. If greater than 1.0 ohm, test the ground circuit for an open/high resistance.
  11. Connect the harness connector of the rear compartment lid latch.
  12. Connect a 3-amp fused jumper wire between the relay switch voltage supply circuit and the relay switch control circuit. Verify the rear compartment lid latch is activated
  13. If the rear compartment lid latch is not activated, test the relay switch control circuit for an open/high resistance. If the circuit tests normal, test or replace the rear compartment lid latch.
  14. Connect a test lamp between the relay coil control circuit and the relay coil voltage supply circuit.
  15. Press the liftgate touch pad switch. The test lamp should momentarily turn ON each time the solenoid is commanded ON.
  16. If the test lamp remains ON all the time, test for a short to ground on the relay coil control circuit. If the circuit tests normal, replace the BCM.
    If the test lamp remains OFF all the time, test for a short to voltage or an open/high resistance on the relay coil control circuit. If the circuit tests normal, replace the BCM.
  17. If all circuits/connections test normal, replace the trunk relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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