A Hall effect measuring device under the hood of a motor vehicle includes a housing, a Hall effect sensor including a holed magnet and a chip arranged at the Gaussian zero point of the magnet, and a ferromagnetic target including a measurement surface in which the chip is securely attached to the magnet, and defines a measurement plane. The sensor and the ferromagnetic target are arranged to be imparted with a relative motion with respect to one another, the sensor being positioned in the housing and configured to measure the value of the magnetic field of the magnet, vertically in line with the chip, on a measurement axis perpendicular to the measurement plane based on relative translational motion and on relative rotational motion.