* Refer to the appropriate replacement procedure for the component causing the condition.
* Control Module References (See: Testing and Inspection/Programming and Relearning) for BCM replacement, setup, and programming
* 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 B2645 03
- Ambient Light Sensor Circuit Voltage Below Threshold
DTC B2645 07
- Ambient Light Sensor Circuit Voltage Above Threshold
Diagnostic Fault Information
The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary depending
on outside lighting conditions. The body control module (BCM) provides a 5 V reference signal to the ambient light sensor. The BCM monitors the
ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp
control (ALC) when the headlamp switch is in the AUTO position. In daylight conditions, the BCM will command the DRLs ON. In low light
conditions, when the headlamps switch is in AUTO position, the BCM will command the low beam headlamps ON.
Conditions for Running the DTC
Battery voltage must be between 9-16 V.
Conditions for Setting the DTC
The BCM detects voltage is below 0.196 volt in the ambient light sensor signal circuit.