Home >> Land Rover >> 2013 >> Range Rover Sport HSE >> Repair and Diagnosis >> General Information >> DTC Index >> Diagnostic Trouble Code Index DTC: Automatic Temperature Control Module (ATC) -- Range Rover Sport/L320 >> Diagnostic Trouble Code Index DTC: Automatic Temperature Control Module (ATC) >> Description And Operation >> DTC U0166-87 Lost Communication With Auxiliary Heater Control Module - Missing message >> Possible Causes