An engine mounted to a vehicle includes at least one manipulation member
used for control of output of the engine. An electronic control unit
controls the manipulation member in accordance with the driving condition
of the engine. When it is determined that there is an abnormality in the
electronic control unit, the amount of air drawn into the engine is fixed
to a predetermined value and the amount of manipulation of the
manipulation member is restricted. When the rotational speed of the
engine becomes higher than the predetermined speed, the electronic
control unit determines that there is an abnormality relating to the
manipulation of the manipulation member.