Speed Sensor
The speed sensor is a contactless type and it detects rotating speeds of a wheel. It is composed of a permanent magnet and coil. When gear pulsers attached to rotating parts of each wheel (rear wheel: outboard joint of driveshaft, front: hub bearing unit) turn, magnetic flux around coil in speed sensor alternates, generating voltages with frequency in proportion to wheel rotating speed. These pulses are inputted into control unit and control unit identifies wheel speeds. See Figure .