• | 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. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Rear Fog Lamp Relay Control | B2540 02 | B2540 05 | B2540 05 | -- |
Rear Fog Lamp Switch Signal | B3588 02 | -- | -- | -- |
Rear Fog Lamp Control | 1 | 1 | -- | -- |
Headlamp Switch Ground | -- | 1 | -- | -- |
Rear Fog Lamp Ground | -- | 1 | -- | -- |
1. Rear Fog Lamps Malfunction |
The auxiliary body control module (XBCM) receives a momentary ground signal from the rear fog lamp switch when the switch is activated. The rear fog lamps will remain illuminated until the switch is activated again or when the ignition key is cycled.
System voltage to the XBCM must be 9-16 volts.
The rear fog lamp switch signal circuit is active for longer than 10 minutes.
The rear fog lamps will be disabled.
• | The DTC will be current for as long as the fault is present. |
• | When the fault is no longer present, the DTC will be a history status code. |
• | A history DTC will clear after 50 ignition cycles or with a scan tool using the clear DTCs function. |
Exterior Lighting Systems Description and Operation
Control Module References for scan tool information
Use the scan tool output control for the Auxiliary Body Control Module to activate the rear fog lamps. The rear fog lamps should illuminate.
⇒ | If the test lamp does not illuminate, test the ground circuit for an open/high resistance. |
⇒ | If not the specified value, test the signal circuit terminal 6 for a short to ground. If the circuit tests normal, replace the XBCM. |
⇒ | If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the XBCM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for XBCM replacement, setup, and programming |