Home >> Jaguar >> 2014 >> XK Base, 2D Convertible >> Repair and Diagnosis >> General Information >> DTC Index >> Diagnostic Trouble Code Index DTC: Climate Control Module (HVAC) -- XK/X150 >> Diagnostic Trouble Code Index DTC: Climate Control Module (HVAC) >> Description And Operation >> Climate Control Module [HVAC] >> DTC B1B78-85: Air conditioning system over pressure - Signal above allowable range >> Possible Causes