Mazda 2006 MX-5 Service Highlights page 246

Operation
Front
• As the front ABS sensor rotor rotates, the magnetic flux between the front ABS wheel-speed sensor and the
front ABS sensor rotor change periodically. This periodic change is in proportion to the rotation speed.
• The semiconductor element in the wheel speed sensor detects the change in magnetic flux, and the active
drive circuit converts it to a rectangular wave signal for the current, which is transmitted to the ABS HU/CM.
• For every single rotation of the ABS sensor rotor, 44 rectangular wave pulse signals are output. The CM in the
ABS HU/CM calculates the wheel speed from the periodicity of these pulses.
DETECTION PRINCIPLE
ABS WHEEL-SPEED SENSOR
SEMICONDUCTOR
ELEMENT
ABS SENSOR ROTOR
Rear
• As the ABS sensor rotor rotates, magnetic flux
formed from the permanent magnet varies and
alternating current is formed with an
electromagnetic conductor. Using this alternating
current, rotation speed is expressed as a varying
proportional cycle and from detection of this cycle
the CM part of the ABS HU/CM can then detect
the wheel rotation speed. While the structures of
the front and rear ABS wheel-speed sensor differ,
the operation is the same.
End Of Sie
04–13–12
ANTILOCK BRAKE SYSTEM
ACTIVE DRIVE CIRCUIT
MAGNETIC RUBBER
(MAGNETIC ENCODER)
OUTPUT WAVE PATTERN
ACTIVE DRIVE CIRCUIT
HI
RECTANGULAR
WAVE SIGNAL
LO
SEMICONDUCTOR
ELEMENT
OUTPUT VOLTAGE WAVEFORM
V
AT LOW SPEED
C3U0413S015
AT HIGH SPEED
E5U413ZS5008