Home >> Land Rover >> 2021 >> Defender 110 X >> Repair and Diagnosis (Single Page) >> General Information >> Specifications Index >> Diagnostic Trouble Code Index DTC: Head Up Display (HUD) -- Defender/L663 >> Diagnostic Trouble Code Index - DTC: Head Up Display (HUD) (G2400895) >> Description And Operation >> Head Up Display Control Module (HUDCM) >> DTC B1A85-86: Ambient Light Sensor - Signal Invalid >> Possible Causes