B2545

DTC B2545

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 B2545 00
- Backup Lamps Circuit




Diagnostic Fault Information






Circuit/System Description

When the PRNDL is placed in the REVERSE position, a signal is sent to the body control module (BCM). The BCM then applies voltage through the backup lamps relay control circuit to the BACK/UP lamp relay in the underhood fuse block, inside rearview mirror, and rearview camera module. The BACK/UP lamp relay then illuminates the backup lamps.


Conditions for Running the DTC

* The ignition is ON.
* The backup lamps must be commanded ON.



Conditions for Setting the DTC

The BCM detects a short to ground on the backup lamp relay control circuit when the backup lamps are being commanded ON.


Action Taken When the DTC Sets

The backup lamps do not illuminate.


Conditions for Clearing the DTC

* The conditions for setting the DTC are no longer present.
* A history DTC clears after 100 malfunction-free ignition cycles.
* The BCM receives the clear code command from the scan tool.



Reference Information
Schematic Reference

Exterior Lights Schematics (Exterior Lights Schematics)
Connector End View Reference

Component Connector End Views (Component Connector End Views)
Description and Operation

Exterior Lighting Systems Description and Operation (Exterior 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

Programming and Relearning (Programming and Relearning)for Scan Tool Information


Circuit/System Verification

Ignition ON, activate the Backup Lamps output control on the scan tool. The Backup Lamps parameter in the data list should display On and the backup lamps should illuminate.


Circuit/System Testing

1. Ignition OFF, disconnect the harness connector X2 at the BCM.
2. Ignition ON, vehicle in park, verify the backup lamps are not on.

• If the backup lamps are on, test the backup lamp relay control circuit terminal 22 for a short to voltage. If the circuit tests normal replace the underhood fuse block.

3. Install a 10A fused jumper wire between the relay control circuit terminal 22 and battery voltage. Verify the backup lamps are on.

• If the backup lamps are not on, test the backup lamp relay control circuit for an open/high resistance or short to ground. If the circuit tests normal replace the underhood fuse block.

4. If all circuits test normal, replace the BCM.



Repair Instructions

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

* Underhood Electrical Center or Junction Block Replacement (Underhood Electrical Center or Junction Block Replacement)
* Programming and Relearning (Programming and Relearning)for BCM, inside rearview mirror, and rearview camera module replacement, setup, and programming