1968 Shelby GT500

Vehicle Speed Sensor (VSS)

The Vehicle Speed Sensor (VSS) is a small signal generator that is turned by a gear inside the transmission assembly. The Vehicle Speed Sensor produces 8 pulse per rotation which a stock computer assumes 8000 pulses per mile. The Vehicle Speed Sensor (VSS) is a variable reluctance sensor that generates a waveform with a frequency that is proportional to vehicle road speed. When the vehicle is moving slowly, the sensor produces a low frequency signal. As the vehicle speed increases, the sensor produces a higher frequency signal The Vehicle Speed Sensor (VSS) supplies this signal to the components that require vehicle speed information including the speed control amplifier for cruise control equipped vehicles and computer. The computer uses the VSS signal for emmisions contol programs and speed limiters. The emmisions programing can cause a manual transmission vehicle to stall out while decelerating if no VSS is used.


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