I have a 98 4x4 Expedition, and the abs light stays on. I replaced the rear sensor on the differential, yet it is still on. Are there any sensors on the front? What about the abs control module? Is the abs run by the main computer, or does it have a separate computer that can't be read by the OBDII code reader?

 

I would just brink to the dealer ...but im sure that the abs has its own computer..should be located by the mast cylinder....did you check your fuse...or try resetting the computer...?