Tuesday, June 25, 2019

2019 Cadillac Truck Escalade AWD V8-6.2L Diagnostic Instructions Page 598


* 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



B2645



DTC B2645



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 B2645 03



- Ambient Light Sensor Circuit Voltage Below Threshold



DTC B2645 07



- Ambient Light Sensor Circuit Voltage Above Threshold



Diagnostic Fault Information



Circuit/System Description



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



B2645 03



The BCM detects voltage is below 0.196 volt in the ambient light sensor signal circuit.

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