9000 Hatchback L4-2290cc 2.3L DOHC Turbo EFI (1994)
Wheel Speed Sensor: Description and Operation
Wheel Sensor Sensors (Part 1 Of 2)
Wheel Sensor Sensors (Part 2 Of 2)
The wheel sensors operate on the generator principle, i.e. a current is induced in a conductor by distortion of the magnetic field surrounding it. Distortion
of the magnetic field around the sensor is caused by the toothed sensor as it passes the sensor body: each time a tooth passes the sensor, the magnetic
field is reinforced. Each time a gap between the teeth passes the sensor, the magnetic field is weakened. Put simply, this means that a positive (+) current
is generated by each tooth and a negative (-) current by each gap between the teeth. This gives rise to an alternating current, the frequency and amplitude
of which (the number of cycles per second and half the peak-to-peak value respectively) varies with the speed at which the sensor wheel is turning. From
this signal, the Electronic Control Unit (ECU) ran deduce the speed of rotation of the wheel.
Front-Wheel Sensor And Sensor Wheel
Each sensor has a trigger sensor wheel, which is press-fitted onto the constant velocity joint. The sensor wheel cannot be removed.
The front wheel sensors are mounted radially relative to the trigger wheel on the steering swivel member.
The sensor leads can be disconnected by means of a connector in the engine compartment.
Rear-Wheel Sensor And Sensor Wheel
Because the sensor is orientated axially relative to the sensor wheel, the design of the rear sensor wheels is different to that of the front ones. The
sensor wheel is press-fitted onto the rear-wheel hub and cannot be removed.
The sensor leads can be disconnected by means of a connector underneath the rear seat.
