Audi 80 Quiz
Anti-lock brake system

Wheel Speed Sensors

In this manual: Anti-lock brake system
Technical Description — 39Engines — 41Exhaust System — 13Cooling System — 28Fuel tank and fuel pump — 12Air Filter and Intake Ducts — 13Mono-Motronic Injection System — 18Digifant Injection System — 19KE-III-Jetronic Injection System — 35MPI and MPFI Injection Systems — 32Clutch — 11Transmission and Driveline — 21Suspension and Steering — 33Brake System — 41Anti-lock brake system — 8Wheels and Tires — 13Body Electrical System — 35Ignition System — 24Lighting — 14Signaling Devices — 7Instruments and Auxiliary Equipment — 54Heating and Ventilation — 7Body Components — 18Troubleshooting — 6Specifications — 13
~1min read

The wheel speed of each individual wheel is detected by a wheel speed sensor (four in total), which transmits this information to the control unit. In turn, the control unit sends commands to the hydraulic unit.

The wheel speed sensors themselves consist of a magnetic core and a coil, and are installed at a small distance from the toothed sensor ring (rotor). As the name suggests, the rotor rotates together with the wheel, so the toothed projections around its circumference pass the sensor faster or slower depending on the speed. Each tooth passing the sensor causes a brief increase in voltage in the sensor. In this way, an electrical pulse is generated in the sensor whose frequency changes in accordance with the wheel speed. The resulting signal is processed in the control unit as wheel speed information. The rotors are located at the front on the outer CV joints of the drive shafts and at the rear on the wheel hubs.

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