Home >> Land Rover >> 2021 >> Defender 110 S >> 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 B1D24-64: Glow Plug - Signal plausibility failure >> Possible Causes