2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 591
* 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 Descriptor
DTC B2657 02
- Ignition Switch Halo Lamp Circuit Short to Ground
Diagnostic Fault Information
Circuit/System Description
The body control module (BCM) supplies a voltage reference through the backlight dimmer switch, which is part of the headlamp switch. When the
dimmer switch is placed in a desired brightness position, reference voltage is applied through the backlight dimmer switch to the BCM. The BCM
interprets this voltage signal, then applies a pulse width modulated (PWM) voltage through the backlight lamp control circuit. This will illuminate
the ignition mode switch halo lamp.
Conditions for Running the DTC
* The ignition is ON.
* The headlamps or park lamps are ON.
Conditions for Setting the DTC
The BCM detects a short to ground on the ignition switch halo lamp control circuit.
Action Taken When the DTC Sets
The BCM will not illuminate the ignition switch halo lamp.
Conditions for Clearing the DTC
* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 100 consecutive malfunction ignition cycles have occurred.
Reference Information
Schematic Reference
Interior Lights Dimming Schematics (See: Diagrams/Electrical Diagrams/Lighting and Horns/System Diagram/Interior Lights Dimming
Schematics)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views/Connector End Views By Name)
Description and Operation
Interior Lighting Systems Description and Operation (See: Lighting and Horns/Description and Operation/Interior Lighting Systems)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
