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. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
TBC 5 Fuse B+ | 1 | 1 | -- | -- |
Backup Lamp Control | B2550 00 | B2550 00 | B2550 00 | -- |
Left Backup Lamp Ground | -- | 1 | -- | -- |
Right Backup Lamp Ground | -- | 1 | -- | -- |
1. Backup Lamps Malfunction | ||||
Circuit/System Description
When the Body Control Module (BCM) receives a class 2 message from the Powertrain Control Module (PCM) requesting to illuminate the backup lamps, battery voltage is sent directly from the BCM through the backup lamp control circuit to the backup lamps. The left backup lamp is always grounded at G401 and the right backup lamp is always grounded at G402.
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 Verification
Ignition ON, command the Backup Lamps ON and OFF with a scan tool. The Backup Lamps should turn ON and OFF between the commanded states.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the inoperative backup lamp.
- Test for less than 5.0 ohms between the ground circuit terminal A and ground.
- Connect a test lamp between the control circuit terminal B 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, programming, and setup. |
