NC Training Guide - Miata.net

04 BRAKESAnti-lock Brake SystemABS Wheel Speed Sensor and ABS Sensor Rotor Construction OperationFront Construction• The front ABS wheel-speed sensorutilizes a semi-conductor elementthat contains an active drive circuit(MR element*). The front sensor isinstalled on the front wheel hub.• The front ABS sensor rotor utilizesa magnetic encoder system thatfunctions with magnetic rubber andis integrated into the wheel hubcomponent. Therefore, if there isany malfunction of the front ABS sensor rotor, replace the wheel hub component.*: A magneto-resistive force means that an exterior magnetic fi eld acts on theelement, changing the resistance of the element.Front Operation• As the front ABS sensor rotor rotates, the magnetic fl ux between the front ABSwheel-speed sensor and the front ABS sensor rotor change periodically. Thisperiodic change is in proportion to the rotation speed.• The semiconductor element in the wheel speed sensor detects the change inmagnetic fl ux and the active drive circuit converts it to a rectangular wave signalfor the current, which is transmitted to the ABS HU/CM.• For every single rotation of the ABS sensor rotor, 44 rectangular wave pulsesignals are output. The CM in the ABS HU/CM calculates the wheel speed fromthe frequency of these pulses.Mazda Technical TrainingMX-5 Miata New Model TrainingSG-127