B2545

DTC B2545 or B3880

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (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 B2545 00
- Rear Left Reverse Light Circuit Malfunction

DTC B3880 00
- Rear Right Reverse Light Circuit Malfunction




Diagnostic Fault Information






Circuit/System Description

Automatic Transmission

When the transmission is placed in the REVERSE position, the transmission control module (TCM) sends a serial data message to the rear electrical center (REC). The message indicates that the gear selector is in the REVERSE position. The REC applies battery voltage to the backup lamps control circuit illuminating the backup lamps. Once the driver moves the gear selector out of the REVERSE position, a message is sent by the TCM via serial data requesting the REC to remove battery voltage from the backup lamps control circuit.


Conditions for Running the DTC

* Battery voltage must be between 9-16 volts.
* Backup lamps ON.



Conditions for Setting the DTC

B2545 00

The DTC will set when the REC detects a short to ground or an open/high resistance in the left backup lamp control circuit when the left backup lamp is being commanded ON.

B3880 05

The DTC will set when the REC detects a short to ground or an open/high resistance in the right backup lamp control circuit when the right backup lamp is being commanded ON.


Actions Taken When the DTC Sets

The REC will disable the backup lamp control circuit that has a fault present.


Conditions for Clearing the DTC

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



Reference Information
Schematic Reference

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

Component Connector End Views (Connector 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

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


Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the inoperative backup lamp.
2. Ignition OFF, exterior lamps OFF, test for less than 5.0 ohms between the appropriate ground circuit terminal listed below and ground.

* Left tail lamp assembly ground circuit terminal 1 - 3 Door
* Left tail lamp assembly ground circuit terminal 6 - 5 Door
* Right tail lamp assembly ground circuit terminal 6 - 3 Door
* Right tail lamp assembly ground circuit terminal 1 - 5 Door


• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the appropriate control circuit terminal listed below and ground.

* Left backup lamp control circuit terminal 2 - 3 Door
* Left backup lamp control circuit terminal 1 - 5 Door
* Right backup lamp control circuit terminal 5 - 3 Door
* Right backup lamp control circuit terminal 6 - 5 Door

4. Command the Reverse Light Test 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 REC.


• 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 REC.

5. If all circuits test normal, replace the inoperative tail lamp circuit board.



Repair Instructions

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

* Tail Lamp Circuit Board Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for REC replacement, setup, and programming