245 / 1265
1.2L REVOTRON ENGINE
207
V. WHEEL SPEED SENSOR
COMPONENT DETAILS
The Wheel speed sensor in vehicle is connected
to a voltage source for operation (active sensor).
It is used in conjunction with a ferrous Toner
wheel and supplies a signal with constant
amplitude pulses whose frequency varies with the
wheel speed. It uses Hall Effect principle, it has a
semiconductor chip with the electronic circuitry for
supply and signal processing integrated on it.
This chip is located within an almost completely
insulated magnetic circuit consisting of permanent
magnet and pole elements. The wheel speed
sensor is mounted directly above the non-
magnetized toner wheel. The magnetic toner
wheel is a ring with teeth on it. The toner wheel is
fitted on to the wheel hub. The alternating teeth
and gap that accompanies the wheel rotation
induces differential magnetic flux density, thus
leading to the variation in the voltage induced in
the semiconductor chip. The signal conditioning
circuit converts this voltage variation into constant
amplitude current pulses. The frequency of these
pulses depends up on the wheel speed. This
measurement principle permits zero speed
measurement.
Precise alignment and gap between the stator
pole and the Toner wheel is vital. To obtain
correct signal, the specified gap between the end
of sensor and the toner ring must be maintained.
SENSOR LOCATION
Wheel Speed Sensor (Front)
Wheel Speed Sensor (Rear)