Home >> Land Rover >> 2020 >> Defender 110 S >> Repair and Diagnosis >> General Information >> Specifications Index >> Diagnostic Trouble Code Index DTC: CHASIS Control Module (CHCM) -- Defender/L663 >> Diagnostic Trouble Code Index - DTC: Chassis Control Module (CHCM) (G3139555) >> Description And Operation >> Chassis Control Module (CHCM) >> DTC U201A-54: Control Module Main Calibration Data - Missing calibration >> Possible Causes