A valve having a housing, a flap rotatably arranged in the housing and connected to a drive shaft mounted in the housing, an electric motor for driving the drive shaft, having a gearing which has at least one toothed segment and which is arranged between the electric motor and the drive shaft, and a sensor, which has a magnet, for determining the angle of rotation of the flap. The toothed segment has at least two detent hooks that engage around the magnet. Furthermore, at least one spring element is provided which preloads the magnet against the detent hooks.