Awheel speed sensor (WSS) or vehicle speed sensor (VSS) is a type of tachometer. It is a sender device used for reading the speed of a vehicle's wheel rotation . It usually consists of a toothed ring and pickup. Typesof Wheel Speed Sensors. Vehicles commonly use two-wheel speed sensors: Magnetic inductive sensor. Hall effect sensor. The magnetic inductive sensor relies on a toothed wheel or a tone ring with magnetic properties. In contrast, the Hall effect sensor uses a magnet and a semiconductor to detect wheel speed. Chapter1: Animation and Commercial Vehicle Wheel Speed Sensor Market Product Definition, Product Types, Volume, and Revenue Analysis of Each Type in North America, Europe, Asia-Pacific, Latin Thepassive speed sensor creates its own AC signal that changes frequency with wheel speed. This signal is only present while the wheel is turning at a rate fast enough to create the AC signal. Vehicles equipped with passive wheel speed sensors do not read at or below 2 mph coming from a dead stop. During a wheel-spin condition, or under a Thevehicle speed sensor, also known as a transmission speed sensor or output shaft speed sensor, plays an active role in your car's transmission and cruise control systems. There are also ABS wheel speed sensors (WSS) on a vehicle's wheel hubs (both on the front axle and rear axle). Apassive sensor creates an AC signal that changes frequency as the wheel changes speed. The ABS control module converts this AC signal to a digital signal for interpretation. It monitors all-wheel speed inputs. Themerging and processing of the individual wheel speed sensor signals by the control unit provide a single reference speed which is roughly the vehicle speed. A comparison of any individual wheel speed with the reference speed supplies the wheel to road slip (wheel tending to lock) signal. Thesensor is mounted at a specific gap from a toothed reluctor ring. As the teeth pass by the wheel speed sensor, it changes the magnetic field and produces alternating current or AC voltage. The AC voltage can be seen by a scope as a sine wave. The voltage signal will increase in amplitude with an increase in the speed of the reluctor ring. Theoutput of a speed sensor is highly dependent upon application details such as the size, shape and material of the target. Target types vary significantly, for example spinning gears, turbine blades, a screw embedded in a turning shaft, or a ferrous metal notch on a conveyor belt. Mostfactory ABS wheel speed sensors will be a two-wire Hall Effect type. These are powered sensors that produce a square wave pulsed output unlike a non-powered variable reluctance sensor that will produce a sine wave output. MdAs8.