Car control unit

[Object] The present invention relates to a car control unit and more particularly to the power source control method of the control unit according to the control unit temperature or the control of a semiconductor device in the control unit. A problem arises that when the temperature of the semiconductor used in the control unit rises beyond the operation guarantee temperature range thereof, the prevention of malfunctions of the control unit and the safety of the car are not taken into account. [Means for Settlement] The temperature of the throttle device 10 is detected using the thermistor 23, and the device temperature is compared with the reference temperature for comparison by the comparator 25, and depending on the comparison result, the relay 12 for controlling the power supply to the throttle device 1 is controlled. [Effects] When the temperature of the throttle control unit rises higher than the reference temperature, the main power source of the throttle device 1 is interrupted, thus the throttle device 1 can be prevented from malfunctions.