ABS light came on / loss of odometer / spedometer

[Windstartled]

Originally Posted by buddy0310

looking at buying a 2000 ford windstar from a garage I trust but the speedometer doesnt work right at aprox 50mph it reads 30mph. the tach and odometer are both working fine any ideas? Also the OD off light came on and started flashing at me

Had exact same problem with the speedometer and was told only two factors can cause this: bad VSS or dead wheel sensor. With regards to the latter Windstar owners community appear to be divided over the issue of whether or not Ford uses rear wheel sensor input to feed speedometer or just VSS. FWIW my opinion is that VSS is mainly used to regulate shifting, not report speed to speedometer. But obviously rear wheel sensor input has to go through the VSS somehow otherwise spinning front wheels in mud ice or snow would cause VSS to shift even though the vehicle is not moving.

With regards to OD OFF flashing. Like many Ford owners I have to deal with that every winter and short of installing a transmission fluid heater not much can be done about it. Even though the flashing sometimes points to very serious tranny issues, most of the time it just means the transmission fluid is too thickened by cold weather to shift smoothly and that until it warms up (about 5 minutes driving) tranny won't shift in 2nd gear unless you do it manually, and forget 3rd gear. This is extremely annoying, but survivable and seasonal. I think there are transmission fluid additives available that cure this but I never tried any myself.