B2555

DTC B2555

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (with HP2) (Initial Inspection and Diagnostic Overview)Diagnostic System Check - Vehicle (without HP2) (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy 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 Descriptors
DTC B2555 01
- Passenger Compartment Lamp Control Circuit Short to Battery

DTC B2555 02
- Passenger Compartment Lamp Control Circuit Short to Ground

Diagnostic Fault Information





Circuit/System Description

When the body control module (BCM) signals for courtesy lamp operation, a message is sent over the GMLAN serial data circuit to the driver door and passenger door switches. The driver door switch and passenger door switch the applies battery voltage to the left and right courtesy lamp control circuits illuminating the door courtesy lamps. The driver door and passenger door switches also provide ground to the lamps.

Conditions for Running the DTC

* Battery voltage must be between 9-16 volts.
* A message is sent from the BCM over the GM LAN serial data circuit to the driver door and passenger door switches to active the door courtesy lamps.

Conditions for Setting the DTC

B2555 01

This DTC will set when the driver or passenger door switch detects a short to voltage in the courtesy lamp control circuit.

B2555 02

This DTC will set when the driver or passenger door switch detects a short to ground in the courtesy lamp control circuit.

Action Taken When the DTC Sets

B2555 01

When this DTC is present, the door courtesy lamps will remain illuminated.

B2555 02

When this DTC is present, the door courtesy lamps will be inoperative.

Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.
* A scan tool CLEAR DTCs command is issued for that switch module.
* A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Reference Information
Schematic Reference

Interior Lights Schematics (Interior Lights Schematics)
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. Disconnect the X2 harness connector at the inoperative door module.
2. Verify that a test lamp illuminates between the ground circuit terminal 15 and B+.

• If the test lamp does not illuminate, test the ground circuit for an open/high resistance. If the circuit tests normal replace the affected door module.

3. Connect a test lamp between the control circuit terminal 10 and the ground circuit terminal 15.
4. Command the Puddle/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 inoperative door module.
• 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 inoperative door module.

5. If all circuits test normal, test or replace the courtesy lamp bulb.

Repair Instructions

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

Control Module References (Programming and Relearning) for driver or passenger door switch replacement, setup, and programming