Honda Acura NSX 1991 Service Manual page 718

Speed Sensor
The speed sensor is a contactless type and it detects the rotating speeds of a wheel. It is composed of a permanent
magnet and coil. When the gear pulsers attached to the rotating parts of each wheel (rear wheel: outboard joint of the
driveshaft, front: hub bearing unit) turn, the magnetic flux around the coil in the speed sensor alternates, generating
voltages with frequency in proportion to wheel rotating speed. These pulses are inputted into the control unit and the
control unit identifies the wheel speeds.
t
GEAR PULSER
at HIGH SPEED
VOLTAGE
PERMANENT
MAGNET
OUTPUT
OW SPEED
SPEED SENSOR