2010 Cadillac Truck Escalade RWD V8-6.0L Hybrid Page 621

2010 Cadillac Truck Escalade RWD V8-6.0L Hybrid Page 621

瀚慖f the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.

瀚慖f the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace

the BCM.

11. If all circuits test normal, test or replace the fog lamp relay.

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

* Relay Replacement (Attached to Wire Harness) (See: Power and Ground Distribution/Power Distribution Relay/Service and Repair/Relay

Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (See: Power and Ground Distribution/Power

Distribution Relay/Service and Repair/Relay Replacement (Within an Electrical Center))

* Front Fog Lamp Replacement (Tahoe, Avalanche) (See: Lighting and Horns/Fog/Driving Lamp/Service and Repair/Removal and

Replacement/Front Fog Lamp Replacement (Tahoe, Avalanche))Front Fog Lamp Replacement (Yukon) (See: Lighting and

Horns/Fog/Driving Lamp/Service and Repair/Removal and Replacement/Front Fog Lamp Replacement (Yukon))Front Fog Lamp

Replacement (PLATINUM) (See: Lighting and Horns/Fog/Driving Lamp/Service and Repair/Removal and Replacement/Front Fog Lamp

Replacement (Platinum))

* Control Module References (See: Testing and Inspection/Programming and Relearning) for BCM replacement, setup, and programming

B2540

DTC B2540

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System

Check - Vehicle) prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an

overview of the diagnostic approach.

* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure

Instructions) provides an overview of each diagnostic category.

DTC Descriptors

DTC B2540 02

- Rear Fog Lamp Control Circuit Short to Ground

DTC B2540 05

- Rear Fog Lamp Control Circuit Short to Battery or Open

Diagnostic Fault Information

Circuit/System Description

When the rear fog lamp switch is placed in the ON position, ground is applied to the auxiliary body control module (XBCM) through the rear fog

lamp switch circuit. The XBCM then applies voltage to the rear fog lamp control circuit to the rear fog lamp.

Conditions for Running the DTC

* Battery voltage must be between 9-16 V.

* Rear fog lamps ON.

Conditions for Setting the DTC

B2540 02

The BCM detects a short to ground in the rear fog lamp switch signal circuit.