Steering angle sensor is installed under the clock spring. Steering angle sensor input to AFLS ECU uses CAN communication in order to measure for speed of steering wheel's operation and angle.Steering angle sensor is composed with main gear and sub gear1, sub gear2 to determine for rotation direction.According to rotation of steering wheel, If the main gear rotate, sub gear1 and sub gear2 be retated. Steering angle sensor calculate rotation angle use MR effect of magnetic that installed in sub gear and different gear ratio sub gear1 and sub gear2. AFLS(Adaptive Front-Lighting System) provides driver with the best visibility uses steering angle sensor's signal.