A vehicle including an internal combustion engine and a stepped transmission including an input shaft and an output shaft, wherein the stepped transmission speed-changes power input to the input shaft while changing a shift speed and outputs the speed-changed power to the stepped transmission output shaft; a control unit that controls the engine and the stepped transmission in accordance with an output request from an operator. The vehicle also including input and output shaft rotation speed detecting units and an output limiting unit that limits the output of the engine by comparing the deviation of the input and output shaft rotation speed to a predetermined rotation speed relationship range. The vehicle also including an abnormality determining unit to determine that an abnormality has occurred in the stepped transmission when the rotation speed relationship exceeds the range of the predetermined rotation speed relationship for at least a first predetermined time period.