Home >> Jaguar >> 2014 >> XF Base >> Repair and Diagnosis >> Quick Lookups >> DTC Index >> Diagnostic Trouble Code Index DTC: Engine Control Module (ECM) GTDI 2.0L Petrol -- XF/X250 >> Diagnostic Trouble Code (DTC) Index DTC: GTDI 2.0L Petrol DTC: Engine Control Module (ECM) >> Description And Operation >> DTC P0504-27: Brake Switch A F/B Correlation - Signal rate of change above threshold >> Possible Causes