An ECU executes a program including the steps of: when a switching valve is controlled to be closed (YES at S1000), comparing exhaust gas's temperature, as detected, with a map value (S1100); if the exhaust gas's temperature is larger than the map value (YES at S1110), determining that the switching valve normally operates (S1300); and if the exhaust gas's temperature is smaller than the map value (NO at S1100), determining that the switching valve has abnormality.