Method for detecting malfunctioning in the exhaust flap valve and/or in the intake conduit valve

The method for determining sensor function of an exhaust valve involves measuring the throttled input air flow for comparison to a preset target value. For sensor diagnosis for the exhaust valve the measurement can be carried out at higher engine speeds. The measurement can be carried out at lower speeds for the suction pipe switching valve. The sensed flow values are used to control the valve.