Home >> Jaguar >> 2017 >> XJR L >> Repair and Diagnosis >> General Information >> DTC Index >> Diagnostic Trouble Code (DTC) Index DTC: Headlamp Leveling Control Module (HLCM) -- XJ/X351 >> DIAGNOSTIC TROUBLE CODE (DTC) INDEX DTC: Headlamp Leveling Control Module (HLCM) >> Description And Operation >> Headlamp Leveling Control Module (HLCM) >> U0001-81 High Speed CAN Communication Bus - Invalid serial data received >> Possible Causes