2010 Cadillac Truck SRX FWD V6-3.0L Page 300

2010 Cadillac Truck SRX FWD V6-3.0L Page 300

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

* Headlamp Replacement (See: Lighting and Horns/Headlamp/Service and Repair/Removal and Replacement/Headlamp Replacement)

* 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))

* Control Module References (See: Testing and Inspection/Programming and Relearning) for headlamp control module replacement, setup

and programming

B257B

DTC B1405, B1529, or B257B

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 B1405 02

- Control Module Voltage Reference Output 2 Circuit Short to Ground

DTC B1405 03

- Control Module Voltage Reference Output 2 Circuit Low Voltage

DTC B1405 07

- Control Module Voltage Reference Output 2 Circuit High Voltage

DTC B1529 03

- Control Module Voltage Reference Output 5 Circuit Low Voltage

DTC B1529 07

- Control Module Voltage Reference Output 5 Circuit High Voltage

DTC B257B 03

- Lighting Control Switch Signal Low Voltage

DTC B257B 07

- Lighting Control Switch Signal High Voltage

Diagnostic Fault Information

Circuit/System Description

The body control module (BCM) supplies battery positive voltage to the backlight dimmer switch, which is part of the headlamp switch. When the

backlight dimmer switch is placed in a desired brightness position, reference voltage is applied to the BCM. The BCM interprets this voltage signal,