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 Instructionsprovides an overview of each diagnostic category.

DTC Descriptors
DTC B2545 01
- Backup Lamps Control Circuit Short to Battery

DTC B2545 02
- Backup Lamps Control Circuit Short to Ground

DTC B2545 04
- Backup Lamps Control Circuit Open

Diagnostic Fault Information






Circuit/System Description

When the transmission is placed in reverse gear, the engine control module (ECM) sends a serial data message to the body control module (BCM). The message indicates that the gear selector is in the reverse position. The BCM applies battery voltage to the backup lamps. The backup lamps are permanently grounded. Once the driver moves the gear selector out of the reverse position, a message is sent by the ECM via serial data requesting the BCM to remove battery voltage from the backup lamp control circuit.

Conditions for Running the DTC

Reverse Gear engaged

Conditions for Setting the DTC

B2545 01

The BCM detects a short to voltage on the control circuit.

B2545 02

The BCM detects a short to ground on the control circuit.

B2545 04

The BCM detects an open control circuit.

Action Taken When the DTC Sets

The backup lamps are inoperative.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information
Schematic Reference

Exterior Lights Schematics Exterior Lights Schematics
Connector End View Reference

Component Connector End Views Hybrid/EV Battery Pack X1 A4
Description and Operation

Exterior Lighting Systems Description and Operation Exterior Lighting Systems
Electrical Information Reference

* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Control Module Referencesfor scan tool information

Circuit/System Verification

Ignition ON, perform the Backup Lamps test. The backup lamps should be ON/OFF.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the E5 backup lamp.
2. Test for less than 5 ohm between the ground circuit terminal B and ground.

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

3. Connect a test lamp between the control circuit terminal A ground.
4. Command the Backup Lamps test 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 K9 BCM.
• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the K9 BCM.

5. If all circuits test normal, replace the E5 backup lamp.

Repair Instructions

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

* Tail Lamp Replacement Tail Lamp Replacement
* Control Module References Control Module Referencesfor control module replacement, programming and setup