The invention relates to an adjustment drive of a motor vehicle, wherein the adjustment drive includes a drive motor having a motor magnet that generates a magnetic exciter main field and having a motor armature that is rotatably arranged between a plurality of magnet poles of said motor magnet. The adjustment drive also includes a magneto-sensitive sensor positioned in such a way that during a rotation of the motor armature it senses a change in a magnetic flux density of the exciter main field.