For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptor

DTC B2545 00: Backup Lamps Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Backup Lamps Voltage Supply | B2530 | 1 | 1 | --
1. Backup Lamps Inoperative

### 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 voltage supply circuit to the left and right backup lamps.

### Conditions for Running the DTC

The battery voltage must be between 9-16 volts.

### Conditions for Setting the DTC

DTC B2545 is set either when the backup lamps supply voltage circuit is shorted to ground or opened, or if the CHMSL/Bkup fused voltage supply circuit to the BCM is shorted to ground or opened.

### Action Taken When the DTC Sets

The backup lamps will not illuminate.

### 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.

• | History DTCs can be cleared using a scan tool.

### Reference Information

#### Schematic Reference

Exterior Lights Schematics

#### Connector End View Reference

Lighting Systems Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

• | Scan Tool Output Controls

• | Scan Tool Data List

• | Scan Tool Data Definitions

### Circuit/System Verification

1. Perform a visual inspection for loose or poor connections at all related components.
2. Install a scan tool.
3. Turn the ignition to the ON position, with the engine OFF.
4. With a scan tool, select light test and command the backup lamps ON and OFF.

### Circuit/System Testing

1. Place the PRNDL in to the PARK Position. Disconnect both tail lamp assemblies and the inside rearview mirror. Clear the DTC. Using a test lamp connected to ground probe the backup lamps voltage supply circuit at the tail lamps.

⇒ | If the test lamp illuminates, test for a short to ground or open in backup lamps voltage supply circuit. If all circuits/connections test normal, replace the BCM.

⇒ | If the test lamp illuminates, test for a short to ground or an open in the CHMSL/DIMR fuse voltage supply circuit. If all circuits/connections test normal, replace the BCM.

2. Connect one of the tail lamp assemblies and test for the DTC. If the DTC resets replace that tail lamp assembly.

⇒ | If tail lamps test normal, replace the inside rearview mirror.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Tail Lamp Replacement

• | Inside Rearview Mirror Replacement

• | Control Module References for BCM replacement, setup, and programming