B2555

DTC B2555

Diagnostic Instructions

* Perform theDiagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* ReviewStrategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



DTC Descriptor
DTC B2555 00
- Passenger Compartment Lamp Control Circuit




Diagnostic Fault Information






Circuit/System Description

The CTSY LPS fuse supplies battery voltage to the body control module (BCM). When the BCM commands the courtesy lamps ON, it applies battery voltage to the courtesy lamps. When any door is opened, the door open switch contacts close and the BCM receives a door-open input and it will illuminate the courtesy lamps. If the BCM receives a door lock or unlock input or a rear hatch open input, it will illuminate the courtesy lamps.


Conditions for Running the DTC

Battery voltage must be between 9-16 volts.


Conditions for Setting the DTC

The BCM detects a short to voltage in the courtesy lamp relay control circuit.


Action Taken When the DTC Sets

The BCM will deactivate the overhead lamps relay for the remainder of the ignition cycle.


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 Schematics (Interior Lights Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Interior Lighting Systems Description and Operation (Interior Lighting Systems Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the front dome lamp.
2. Connect a test lamp between the control circuit terminal 3 and ground.
3. Ignition ON, command the Courtesy 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 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.




Repair Instructions

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

* Relay Replacement (Attached to Wire Harness) (Relay Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (Relay Replacement (Within an Electrical Center))
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming