The HECU sends requirement data, such as torque reduction, the number of fuel cut cylinders, and the ESP(ESC) control request, to the PCM(ECM & TCM) through CAN bus line. The PCM(ECM) performs the fuel cut function according to a request signal from the HECU and then retards an ignition timing. The PCM(TCM) maintains current gear position during the ESP(ESC) control period in order not to increase power which causes a Kickdown shift.