Yes, the VSS controls the speedo. However, if your VSS is faulty, it'll definitely set a trouble code in your computer and the " Check Engine" light will come on.
Is yours on? If so, have it scanned at AutoZone. They'll do this for free. Then go from there.
If not, then nothing's wrong with your VSS. The problem will lies with the speedo itself, or the gauge cluster's wiring. I'm not sure, but I believe the gauge clusters on your vehicle requires complete replacement.