Vehicle Speed Sensor: Description and Operation

VSS Circuit:

PURPOSE
The PCM/TCM will calculate vehicle speed based on a series of pulses provided by the vehicle speed sensor through the Vehicle Speed Sensor Buffer.

OPERATION
The speed sensor circuit consists of a magnetic induction type sensor, a vehicle speed sensor buffer module and wiring. Gear teeth pressed on the output shaft induce an alternating current in the sensor. This signal is transmitted to the buffer. The buffer compensates for various axle ratios and converts the signal into a square wave for use by the speedometer, cruise control, antilock brakes and PCM/TCM. The buffer sends two different signals to the PCM. The 437 circuit relays the transmission output speed which is used to control shift points, line pressure, TCC, DTC 24.