Wheel Speed Sensor

Rod-shaped wheel speed sensors or impulse sensors are used for measuring wheel speeds. In the three-channel system with three wheel speed sensors installed in our vehicles (excluding vehicles with ASR), the wheel speed of each wheel is measured separately on the front axle.





The left/right front wheel-speed sensors (L6/1 and L6/2) are installed in the steering knuckles.





The rear wheel speed sensor (L6) is located on the rear axle casing (67). The drive pinion serves to measure the mean speed of both mar wheels.





The wheel speed sensors sense wheel speeds by way of the rotor teeth. On the front axle, the rotor teeth (69a) are machined into the front wheel hub (69).

The wheel speed sensors (L6/1 and L6/2) on the front axle have a diameter of 18 mm.





On the rear axle, the rotor is a toothed wheel (121) and pressed onto the drive pinion gear (120). For each rear axle ratio there is a corresponding gear wheel with a different number of teeth. Refer to removal and installation of wheel speed sensor on rear axle for assignment of rotor to rear axle.





Wheel speed sensors consist of a magnetic core and a coil. Rotation of the toothed wheel or rotor, which is located at a given distance in relation to the wheel speed sensor, will change the magnetic field, so that an alternating voltage is induced in the coil. This alternating voltage changes its frequency in accordance with the wheel speed and the number of teeth, i.e. the frequency is proportional to the wheel speed.








The cable (27) of the wheel speed sensor (L6/1 or L6/2) from the stewing knuckle to the coaxial plug in the engine compartment is routed via the bracket (29, 32) in the wheelhouse.





The wheat speed sensor on the rear axle is connected to the cable harness under the rear seat via the plug connection (L6x).