Home >> Land Rover >> 2021 >> Defender 90 >> Repair and Diagnosis >> General Information >> Specifications Index >> Diagnostic Trouble Code Index DTC: Body Control Module (BCM) -- Defender/L663 >> Diagnostic Trouble Code Index - DTC: Body Control Module (BCM) (G2400885) >> Description And Operation >> Body Control Module (BCM) >> DTC B1B33-81: PATS Challenge Error - Invalid serial data received >> Possible Causes