B2555

DTC B2555

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions 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.

Circuit/System Testing

1. Disconnect the X2 harness connector at the affected 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 affected 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 affected door module.

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

Repair Instructions

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