B2545

DTC B2545

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 Descriptor
DTC B2545
- Backup Lamps Circuit

Circuit/System Description

When the body control module (BCM) receives a class 2 signal from the powertrain control module (PCM) or engine control module (ECM) indicating the gear selector is in the REVERSE position, the BCM applies positive voltage to the backup lamps supply voltage circuit. The backup lamps are grounded at G401 for the left backup lamp and G400 for the right backup lamp.

Conditions for Running the DTC

* The battery voltage must be between 9-16 volts.
* The gear selector must be placed in and out of the REVERSE position.

Conditions for Setting the DTC

* A short to ground, short to voltage, an open, or high resistance in the backup lamp supply voltage circuit.
* A short to ground, open, or high resistance on the battery positive voltage circuit 1240.

Action Taken When the DTC Sets

The backup lamps will not operate properly.

Conditions for Clearing the DTC

* This DTC will clear on current status after the condition for setting the fault is corrected.
* A history DTC will clear after 100 consecutive ignition cycles without a fault present.

Diagnostic Aids

A short to ground in the backup lamp supply voltage circuit may cause the CHMSL BCK/UP fuse to open.

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 ON, place the gear selector in park or neutral.
2. Observe the backup lamps. The backup lamps should not be illuminated.

• If the backup lamps are illuminated, test the backup lamp supply voltage circuit for a short to voltage. If the circuit tests normal, replace the BCM.

3. Ignition OFF, disconnect the X1 harness connector at the BCM.
4. Verify that a test lamp illuminates between the B+ circuit terminal 52 and ground.

• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.

5. Test the backup lamp supply voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

Repair Instructions

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

Control Module References (Programming and Relearning)