The engine speed sensor sends information to the computer telling it
how fast the car is traveling.
The engine speed sensor is designed to record the rate at which the
crankshaft is spinning. This sensor consists of a toothed metal disk
mounted on the crankshaft and a stationary detector that covers a
magnetic coil that the current passes through. As the metal teeth move
past the coil, its magnetic field is disturbed. This causes a stream
of pulses in the current. The computer can calculate engine speed
from the number of rotations of the crankshaft. The number of
rotations are reported by the frequency of the pulses from the engine
speed sensor.
