Home >> Land Rover >> 2021 >> Discovery S >> Repair and Diagnosis (Single Page) >> Quick Lookups >> DTC Index >> Diagnostic Trouble Code Index DTC: HVAC Control Module (HVAC) -- Discovery/L462 >> General Information >> Description And Operation >> Diagnostic Trouble Code Index - DTC: HVAC Control Module (HVAC) (G2016105) >> DTC B1D34-66: Heater In Lock Out Mode - Signal has too many transitions/events >> Possible Causes