i know its abs related  but what exactly not sure, look into the abs system see what you can find, some one is going to help soon.

One of them has to be slightly off, have some one drive the vehicle while looking at this
data at certain different speeds one of them could be acting up, check resistance
values on all of them make sure they are clean, no grease metal particals around
magnets etc, if everything seems ok then suspect a bad module.