Malfunction determining device and method of determining a failure of the control system

The 3CPU motor generator ECU (172) (330), a voltage sensor (180), a voltage sensor (182), a current sensor (192), a temperature sensor (193), a temperature sensor (194), the 1CPU (310), If a signal transmitted by a 2-CPU (320) and the communication circuit (350) is abnormal, it is determined that the control system is abnormal. The 3 CPU (330), when the control system is abnormal, the voltage sensor (180), a voltage sensor (182), a current sensor (192), a temperature sensor (193), a temperature sensor (194), the 1CPU (310), each of the first 2-CPU (320) and the communication circuit (350) is equal to or abnormal.