Home >> Land Rover >> 2017 >> Discovery SE >> Repair and Diagnosis >> Quick Lookups >> DTC Index >> Diagnostic Trouble Code Index DTC: HVAC Control Module (HVAC) -- Discovery/L462 >> Diagnostic Trouble Code Index DTC: HVAC Control Module (HVAC) >> Description And Operation >> DTC B1D34-66: Heater In Lock Out Mode - Signal has too many transitions/events >> Possible Causes