Home › Land Rover › 2021 › Defender 90 › Repair and Diagnosis › General Information › Specifications Index › Diagnostic Trouble Code Index DTC: Transmission Control Module (TCM) -- Defender/L663 › Diagnostic Trouble Code Index - DTC: Transmission Control Module (TCM) (G3187879) › Description And Operation › Transmission Control Module (TCM) - 8HP70/45 Transmissions › DTC P0606-04: Control Module Processor - System internal failures › Possible Causes