Home › Land Rover › 2020 › Defender 110 HSE › Repair and Diagnosis › Quick Lookups › Common Specs & Procedures › 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 B1974-46: Rear View Mirror Module - Calibration/Parameter Memory Failure › Possible Causes