2010 Cadillac Truck SRX AWD 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,
