B256A

DTC B256A

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B256A 04

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Liftgate Lamp Control Circuit Open

Diagnostic Fault Information






Circuit/System Description

When the body control module (BCM) receives a liftgate open signal, the BCM supplies B+ to the rear compartment courtesy lamp control circuit. This will illuminate the rear compartment courtesy lamp.

Conditions for Running the DTC

* Ignition ON.

* The system voltage is between 9-16 V.

Conditions for Setting the DTC

The BCM detects an open circuit on the rear compartment courtesy lamp control circuit.

Action Taken When the DTC Sets

The rear compartment courtesy lamp is inoperative.

Conditions for Clearing the DTC

A current DTC clears when the diagnostic runs and passes.

Reference Information

Schematic Reference

Interior Lights Schematics Interior Lights Schematics

Connector End View Reference

Component Connector End Views Connector End Views By Name

Description and Operation

Interior Lighting Systems Description and Operation Interior Lighting Systems

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Programming and Relearning for scan tool information

Circuit/System Verification

Ignition ON, command the Cargo Lamp ON and OFF with a scan tool. The rear compartment courtesy lamp should turn ON and OFF when changing between the commanded states.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the E8S rear compartment courtesy lamp.

2. Test for less than 5 ohms between the ground circuit terminal 2 and ground.

• 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 1 and ground.

4. Command the Cargo Lamp ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.

• If the test lamp is always OFF, test the control circuit for a short to round or open/high resistance. If the circuit tests normal, replace the K9 BCM.

5. If the all circuits test normal, replace the E8S rear compartment courtesy lamp.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

* Rear Compartment Courtesy Lamp Replacement Rear Compartment Courtesy Lamp Replacement

* Control Module References Programming and Relearning for BCM replacement, programming and setup