Home › Land Rover › 2021 › Defender 90 First Edition › Repair and Diagnosis › General Information › Specifications Index › Diagnostic Trouble Code Index DTC: Rear Differential Control Module (RDCM) -- Defender/L663 › Diagnostic Trouble Code Index - DTC: Rear Differential Control Module (RDCM) (G2400909) › Description And Operation › Rear Differential Control Module (RDCM) › DTC U3000-47: Control Module - Watchdog/safety microcontroller failure › Possible Causes