HEXA

Anti-lock Braking System(ABS)

The accumulator absorbs the surge in brake fluid

that accompanies the pressure reduction phase.

The Damping Chamber suppresses pressure

oscillations within the hydraulic system,

preventing them from being propagated back to

the brake pedal and reduces noise levels in the

system.

B. WHEEL SPEED SENSOR (WSS) :

Working principle:

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.

Refer Repairs section for procedure to check air

gap.

Pin Out :

Pin Details :

PIN NO.

DESCRIPTION

Wheel Speed Sensor Signal

Wheel Speed Sensor Power

Precautions while handling wheel speed

sensor

1. Storage temperature (- 40° C to + 50° C)

should not be exceeded

2. Avoid free fall of the sensor

3. The sensor tip should not be scratched.

4. Sensor should not be exposed to strong

magnetic field.