Wheel Speed Sensor, Location/Task/Design/Function

Wheel Speed Sensor, Location/Task/Design/Function

MODEL 129,
140, 202 as of 1.6.94,
163, 168, 170, 208, 210
with CODE (470a) Anti-lock brake system (ABS)
with CODE (212a) Electronic traction system (ETS)
with CODE (471a) Acceleration slip regulation (ASR)
MODEL 129,
140 as of 1.6.94,
163 up to 31.8.02,
168, 170, 210 with CODE (472a) Electronic Stability Program (ESP)
MODEL 202 with ENGINES 112, 113, 604 with CODE (472a) Electronic Stability Program (ESP)
MODEL 208 with ENGINES 112, 113 with CODE (472a) Electronic Stability Program (ESP)




L6/1 Left front wheel speed sensor
L6/2 Right front wheel speed sensor

ABS only
L6 Rear axle speed sensor

ETS, ASR, ESP only
L6/3 Left rear wheel speed sensor
L6/4 Right rear wheel speed sensor

Wheel speed sensor, location
The front wheelspeed sensors (L6/1 and L6/2) are mounted on the front steering knuckle assemblies.
ABS: The rear wheelspeed sensor (L6) is located on the differential assembly.
ETS, ASR, ESP: The rear wheelspeed sensors (L6/3 and L6/4) are mounted on the rear wheel carriers.

Wheel speed sensor, task
To supply the current wheel speed to the ABS, ETS, ASR or ESP control module (N47-7, N47-2, N47-1 or N47-5).

Wheel speed sensor, design
Inductive sensor: Coil with magnetic core installed at a defined distance from reluctor on the front wheel hub, the rear halfshafts or the drive pinion at the rear axle.

Wheel speed sensor, function
The magnetic field of the wheel speed sensor is intersected by the teeth of a rotor. This changes the magnetic field and the coil induces an AC voltage. The frequency of this alternating current, governed by the number of teeth on the reluctor, fluctuates to reflect variations in wheelspeed, is proportional to wheelspeed.