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 Descriptors

DTC B2545 00: Rear Left Reverse Light Circuit Malfunction
DTC B3880 00: Rear Right Reverse Light Circuit Malfunction

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Backup Lamp - Left Control | B2545 00 | B2545 00 | 1 | --
Backup Lamp - Right Control | B3880 00 | B3880 00 | 1 | --
Left Rear Stop/Turn Lamp Ground | -- | 1 | -- | --
Right Rear Stop/Turn Lamp Ground | -- | 1 | -- | --
1. Backup Lamps Malfunction

### 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

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Exterior Lighting Systems Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References 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 ohms between the appropriate ground circuit terminal listed below and ground.

• | Left tail lamp ground terminal 1 - 3 Door

• | Left tail lamp ground terminal 6 - 5 Door

• | Right tail lamp ground terminal 6 - 3 Door

• | Right tail lamp ground 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 terminal 2 - 3 Door

• | Left backup lamp control terminal 1 - 5 Door

• | Right backup lamp control terminal 5 - 3 Door

• | Right backup lamp control 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 after completing the diagnostic procedure.

• | Tail Lamp Circuit Board Replacement

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