The AHLS(Auto Headlamp Leveling System) is a device that adjusts the headlamp level automatically depending on loading conditions of the vehicle and driving conditions. It also consists of rotor, stator, PCB(Printed Circuit Board) coil and sensor lever and measures the magnetic field of stator parts by rotation of rotor. Despite the parameter of leadlights variation value about vehicle gradient is set, the sensor's angle variation values can not be trusted, if the AHLS(Auto Headlamp Leveling System) ECU does not know the origin position of the height sensor.