2010 Cadillac Truck SRX AWD V6-3.0L Page 458
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,
then applies a pulse width modulated (PWM) voltage to the LED dimming supply circuit to all related interior lamps, illuminating them to the
desired level of brightness.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
B1405 03, B1529 03, or B257B 03
The BCM detects less than 0.3 V on the dimmer switch signal circuit.
