WSS (Wheel Speed Sensor)
The wheel speed sensor is the essential component the ESP (ESC) because the ESP (ESC) module calculates vehicle speed and determines whether wheel lock occurs based on data from the sensor.
For example, front-wheel vehicles use speed of a faster rear wheel as a reference when determining vehicle speed, and if the vehicle detects difference in speed between front and rear wheel, ABS control sets in.
Wheel speed sensor is active hall-sensor type.