Home >> Land Rover >> 2021 >> Defender 110 X >> 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 P186A-13: Differential Lock-up Actuator Brake Control Circuit/Open - Circuit open >> Possible Causes