A method is provided for diagnosing the integrity of a swirl generating system for an internal combustion engine. The swirl generating system includes, but is not limited to swirl controlling elements that are individually located in a respective air passage connecting the intake manifold of the engine to an intake port of an engine combustion chamber, an actuator having a movable shaft, a cinematic chain for mechanically connecting the swirl controlling elements to the actuator movable shaft, an actuator control unit for normally moving the actuator movable shaft in a first direction towards a first final position, and in a second opposite direction towards a second final position, and actuator sensor for sensing the position of the actuator movable shaft. The method providing to arrange at least a mechanical stop for directly acting on one component of the cinematic chain, in order to indirectly limit the movement of the actuator movable shaft in the first direction at a first checking position coincident or beyond the first final position, command the actuator control unit for moving the actuator movable shaft in the first direction towards the first checking position, and verify through the position sensing means whether the actuator movable shaft stops in the first checking position (CP1) or goes beyond.