B2645
DTC B2645
Circuit Description
The body control module (BCM) monitors the ambient light sensor signal circuit in order to determine if the daytime running lights (DRL) or the auto headlights (ALC) should be turned ON in the AUTO mode. When the BCM senses the ambient light sensor voltage is between 1.75-4.9 volts, either the DRL will be commanded ON or the ALC will be commanded ON.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2645 Ambient Light Circuit
Conditions for Running the DTC
The system voltage must be between 9-16 volts.
Conditions for Setting the DTC
* When the ambient light sensor signal voltage is less than 1.75 volts.
* When the ambient light sensor signal voltage is more than 4.9 volts.
* If there is a short to battery positive voltage or a short to ground on the 10-volt reference circuit of the brake pedal position sensor (BPPS).
Action Taken When the DTC Sets
The ALC will remain ON in any ambient light state.
Conditions for Clearing the MIL/DTC
* This DTC will clear immediately after the condition for setting the fault is corrected.
* A history DTC will clear after 100 consecutive ignition cycles without a fault present.
* Use a scan tool in order to clear history and current DTCs.
Test
