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