B2555

DTC B2555

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 B2555 02
- Passenger Compartment Lamp Control Circuit Short to Ground

Diagnostic Fault Information





Circuit/System Description

The body control module (BCM) supplies a voltage reference through the instrument panel cluster dimming voltage reference circuit to the instrument panel cluster lamps dimmer switch. When the dimmer switch is placed in a desired brightness position, reference voltage is applied through the dimmer switch rheostat and the instrument panel cluster lamps dimmer switch signal circuit to the BCM. The BCM interprets this voltage signal, then applies a variable voltage through the LED backlight lamp control circuit illuminating the components listed below:

* Accent Lamp - driver door
* Accent Lamp - passenger door
* Accent Lamp - driver door handle
* Accent Lamp - passenger door handle
* Accent Lamp - over head console

Conditions for Running the DTC

* The ignition is ON.
* The headlamps or park lamps are ON.

Conditions for Setting the DTC

The BCM detects a short to ground on the LED backlight lamp control circuit.

Action Taken When the DTC Sets

The BCM will not dim or illuminate any LED backlighting supplied by the backlight lamp control circuits.

Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 100 consecutive malfunction ignition cycles have occurred.

Reference Information
Schematic Reference

Interior Lights Dimming Schematics (Electrical Diagrams)
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

Command the Interior Ambient Lighting ON and OFF with a scan tool. The appropriate accent lamps should be ON and OFF when changing between the selected states.

Circuit/System Testing

Note: Each back lighted component may need to be disconnected to isolate a short to voltage or short to ground. Use the schematic to identify the following:

* Back lighted components the vehicle is equipped with.
* Component locations on the back lighting dimming control circuit
* Each component's control and ground circuit terminals

1. Ignition OFF, disconnect the harness connector at any component with inoperative backlighting.
2. Ignition OFF, scan tool disconnected, interior lamps OFF, doors CLOSED, test for less than 5 ohm between the ground circuit 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 and ground.
4. Command the Interior Ambient Lighting 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 OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
• 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.

5. If all circuits test normal, test or replace the component with the inoperative backlighting.

Repair Instructions

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

* Courtesy Lamp Replacement (Courtesy Lamp Replacement)
* Control Module References (Programming and Relearning) for BCM, HVAC control module, and radio replacement, setup, and programming