Home >> Land Rover >> 2021 >> Defender 110 X >> Repair and Diagnosis >> General Information >> Specifications Index >> Diagnostic Trouble Code Index DTC: HVAC Control Module (HVAC) -- Defender/L663 >> Diagnostic Trouble Code Index - DTC: HVAC Control Module (HVAC) (G2400894) >> Description And Operation >> HVAC Control Module (HVAC) >> DTC B1B7D-87: Rear Air Distribution Actuator - Missing message >> Possible Causes