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ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
CAUTION:
The ABS is composed of major components as
follows.
Front and rear wheels are equipped with sensors
and sensor rotors respectively.
1
Wheel sensor and the sensor rotor
2
Electronic control unit (ECU)
3
Hydraulic unit (HU)
4
Fail-safe relay
5
ABS harness
In addition, there are relevant parts such as the
ABS warning light in the meter panel, the test con-
nector of ABS harness in the cowling body.
Care should be taken to handle the ABS com-
ponents since they have been accurately ad-
justed and must be kept away from shocks
and dirt.
Among the ABS components, parts of the
ECU, HU, wheel sensor and fail-safe relay
cannot be disassembled.
ABS COMPONENTS FUNCTION
Wheel sensor and the sensor rotor
Wheel sensor 1 detects the wheel rotation speed
and works to send the wheel rotation signal to the
ECU.
It is composed of the permanent magnet and coil.
For a front wheel, it is attached to the sensor hous-
ing 2 and to the crankcase for a rear wheel.
Sensor rotor 3 is pressed in the inner side of
wheel hub with front and rear wheels, then rotates
together with the wheel. Sensor rotor has 36
serration inside and is installed close to the wheel
sensor. Accordingly, the distance changes to the
crest and bottom of teeth as the wheel rotates to
generate the inductive electromotive force in the
wheel sensor. Wheel rotation speed can be thus
detected based on the frequency of this alternat-
ing voltage.
