A VSS (vehicle speed sensor) tells the cars computers how fast you are traveling. Normally to work the speedometer or to let the transmission know when to shift. The camshaft position sensor keeps an eye on the engine speed. It communicates with the pcm to help the car control the fuel injectors, spark, and other driveablitly concerns. Both sensors are normally magnetic sensors with reluctor rings. The vss sensor will be located in the tailshaft of the transmission and the camshaft position sensor is normally located on the motor near the camshaft. If the car is over head cam then the sensor should be in the heads. If the cars motor has the cam in the block then she sensor usually mounts on the block.