Econoline E350 1 Ton V8-7.3L DSL Turbo VIN F (1998)
Vehicle Speed Sensor: Description and Operation
Vehicle Speed Sensor (VSS)
The Vehicle Speed Sensor (VSS) is a variable reluctance or Hail-effect type sensor that generates a waveform with a frequency that is proportional to the
speed of the vehicle. If the vehicle is moving at a relatively low velocity, the sensor produces a signal with a low frequency. As the vehicle velocity
increases, the sensor generates a signal with a higher frequency. The PCM uses the frequency signal generated by the VSS (and other inputs) to control
such parameters as fuel injection, ignition control transmission shift scheduling and torque converter clutch scheduling.