Yes.
Look at the back tire. Side with the caliper and rotor. Just above the brake cable you will find another black cable follow it back. There is a bracket that holds the sensor. The black sensor points directly at the bolts that hold the rotor. I cleaned the side that points at the rotor bolts with a rag and some paint thinner. Did not take anything apart just cleaned. 5 minutes top. Fixed my problem. Apparently enough crud had built up to affect the speedo reading.
Hope this helps.
Dave
Galveston