Home › Land Rover › 2021 › Defender 90 › Repair and Diagnosis › General Information › Specifications Index › Diagnostic Trouble Code Index DTC: Body Control Module (BCM) -- Defender/L663 › Diagnostic Trouble Code Index - DTC: Body Control Module (BCM) (G2400885) › Description And Operation › Body Control Module (BCM) › DTC B1DB6-46: Rear Roof Blind Module - Calibration/parameter memory failure › Possible Causes