Milan FWD L4-2.3L (2008)
Vehicle Speed Sensor: Description and Operation
Output Shaft Speed (OSS) Sensor
The OSS sensor provides the PCM with information about the rotational speed of an output shaft. The PCM uses the information to control and
diagnose powertrain behavior. In some applications, the sensor is also used as the source of vehicle speed. The sensor may be physically located in
different places on the vehicle, depending upon the specific application. The design of each speed sensor is unique and depends on which powertrain
control feature uses the information that is generated.
Vehicle Speed Sensor (VSS)
Typical Vehicle Speed Sensor (VSS)
The VSS is a variable reluctance or Hall-effect 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/transaxle shift scheduling, and torque converter clutch scheduling.
