ABS WHEEL-SPEED SENSOR AND ABS SENSOR ROTOR CONSTRUCTION/OPERATION
id041500105000
Construction
• The ABS wheel speed sensor utilizes a semiconductor element that contains an active drive circuit (Hall element*). The front sensor is installed on the front wheel hub component and the rear sensor is installed on the rear knuckle.
• The front ABS sensor rotor utilizes a magnetic encoder system that functions with magnetic rubber, and is integrated into the front wheel hub component. Therefore, if there is any malfunction of the front ABS sensor rotor, replace the front wheel hub component.
• The rear ABS sensor rotor is integrated with the drive shaft. Therefore, if there is any malfunction of the rear ABS sensor rotor, replace the drive shaft.
*: Hall effect is produced by the Hall element which generates electromotive force in the direction perpendicular to the electrical current and magnetic field when the magnetic field is applied perpendicular to the electrical current.
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Caution
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• When inspecting the ABS wheel speed sensor, do not use a tester to inspect resistance. It is possible that the voltage from the tester could damage the semiconductor inside the ABS wheel speed sensor. Inspect using the PID data monitor of the Mazda Modular Diagnostic System (M-MDS).
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Note
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• Magnetic encoder: A plate that has positive and negative poles (marked out) in a continuous, alternating line.
Front ABS wheel-speed sensor and sensor rotor
Rear ABS wheel-speed sensor and sensor rotor
Operation
• As the ABS sensor rotor rotates, the magnetic flux between the ABS wheel speed sensor and the 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 DSC HU/CM.
• For every single rotation of the ABS sensor rotor, 44 rectangular wave pulse signals are output. The CM in the DSC HU/CM calculates the wheel speed from the periodicity of these pulses.
Front ABS wheel-speed sensor and sensor rotor
Rear ABS wheel-speed sensor and sensor rotor
