Home › Land Rover › 2021 › Defender 90 › Repair and Diagnosis › General Information › Specifications Index › Diagnostic Trouble Code Index DTC: Transfer Case Control Module (TCCM) -- Defender/L663 › Diagnostic Trouble Code Index - DTC: Transfer Case Control Module (TCCM) (G2400921) › Description And Operation › Transfer Case Control Module (TCCM) › DTC P18A4-13: Motion/Position Sensor Power Circuit - Circuit open › Possible Causes