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: Backup Lamps CircuitDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
CHMSL BCK/UP Fuse B+ | B2545 00 | B2545 00 | -- | -- |
Backup Lamps Control | B2545 00 | 1 | 1 | -- |
Backup Lamp - Left Ground | -- | 1 | -- | -- |
Backup Lamp - Right Ground | -- | 1 | -- | -- |
1. Backup Lamps Malfunction | ||||
Circuit/System Description
When the transmission is placed in the REVERSE position, the transmission control module (TCM) sends a GMLAN 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 and the rear object sensor control module. The backup lamps are permanently grounded at G401 for the left and G400 for the right. Once the driver moves the gear selector out of the REVERSE position, a message is sent by the TCM via serial data requesting the BCM to remove battery voltage from the backup lamp control circuit.
Conditions for Running the DTC
Battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
DTC B2545 00 will set when one of the following conditions exist:
| • | The BCM detects a short to ground in the backup lamps control circuit. |
| • | The BCM detects a short to ground or an open/high resistance in the CHMSL BCK/UP fuse voltage supply circuit. |
Actions Taken When the DTC Sets
When DTC B2545 00 is present, the backup lamps will not operate.
Conditions for Clearing the DTC
| • | The condition responsible for setting the DTC no longer exists. |
| • | A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the inoperative backup lamp.
- Ignition OFF, exterior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal B and ground.
- Connect a test lamp between the control circuit terminal A and ground.
- Command the backup lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If all circuits test normal, test or replace the inoperative backup lamp.
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. |
| ⇒ | 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 BCM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
