For the electric power steering (EPS), the combination of the material of the brush of the motor and the steering gear ratio is not appropriate. Therefore, if the steering wheel is repeatedly turned to the maximum whilst the vehicle is not in motion, excessive current may flow through the internal wiring that is for maintaining the motor rotation speed at a constant level. Consequently, there is a risk that a short circuit may occur in the wire, and this could cause the EPS warning light to illuminate and make steering heavier.