GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2007 🢒 Rendezvous - FWD 🢒 Driver Information and Entertainment 🢒 Cellular, Entertainment, and Navigation 🢒 DTC B3826

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 Descriptor

DTC B3826: Cargo Door/Liftgate Unlock Request Circuit Malfunction.

Circuit/System Description

The body control module (BCM) provides grounds for the liftgate latch assembly lock and unlock controls. If the BCM detects a fault in the Liftgate Lock Motor Unlock Control, DTC B3826 is set.

Conditions for Running the DTC

Battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

This DTC will set when the BCM detects a fault in the Liftgate Lock Motor Unlock Control.

Action Taken When the DTC Sets
    • The BCM stores the DTC to memory.
    • The rear compartment lid latch will malfunction.

Conditions for Clearing the DTC
    • This DTC will change from current to history when the fault is no longer present.
    • A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
    • The technician issues a scan tool CLEAR DTCs command.

Reference Information

Schematic Reference

Release Systems Schematics

Connector End View Reference

    •  Vehicle Access Connector End Views
    •  Data Communication Connector End Views

Description and Operation

Rear Hatch/Gate 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

Command the Liftgate Lock Motor and Unlock Motor ON and OFF with a scan tool. The Liftgate Latch Assembly should lock and unlock.

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector C1 at the Liftgate Latch Assembly.
  2. Ignition OFF, test for less than 1.0 ohm of resistance between the control circuit terminal B and ground.
    3. ⇒If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If circuits test normal, replace the BCM.
  3. Ignition OFF, test for less than 1.0 ohm of resistance between the control circuit terminal A and ground.
    4. ⇒If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If circuits test normal, replace the BCM.
  4. Connect a test lamp between control circuit terminal B and control circuit terminal A.
  5. Ignition ON, command the Liftgate Lock to LOCK and UNLOCK with a scan tool. The test lamp should turn ON when commanding the LOCK and UNLOCK states.
    6. ⇒If the test lamp remains OFF during either of the commands, test for a short to ground on either control circuit. If the circuits test normal, replace the BCM.
  6. If all circuits test normal, test or replace the Liftgate Latch Assembly.

Component Testing
  1. Install a 20-amp fused jumper wire between the control terminal A and 12 volts. Momentarily install a jumper wire between the control terminal B and ground. The Liftgate Latch Assembly should perform the LOCK/UNLOCK function.
    2. ⇒If the function does not perform as specified, replace the appropriate Liftgate Latch Assembly.
  2. Reverse the jumper wires; the Liftgate Latch Assembly should perform the LOCK/UNLOCK function.
    3. ⇒If the function does not perform as specified, replace the Liftgate Latch Assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for BCM replacement, setup, and programming.