They tend to do that when abs doesn't work.
1 reset the computer. This can clear a code that has been resolved. Thishappend to for me when ford claimed my "g switch" was bad.
2 replace the rear abs sensor. It should be about 20 bucks. Again reset the computer.
3 clean your front sensors
Now for the pricey and easiest option.
Take it to get the code read. This means dealer. It will cost about an hour of labor minimum for them to read the code and not fix the broken item. They will qoute a you price to repair it if you choose to go that route.
Who really needs abs anyway?
99 x-cab 4x4 4.0l auto
mods, cranked t-bars, silencer delete, k&n drop in, Rebuilt trans ,Trans Go stage 3 shift kit, 3200stall Fuddle Racing Torque Converter,
VANIR 63mm TB, Roush split rear exit exhuast, E-Fan, JBA Headers
Auto up/down both windows, OHC, EATC (soon to be modded)
03 Crown Victoria Police Interceptor