Before doing anything have the ABS codes pulled. A standard OBD2 scanner may not have the ABS abilities but some do. Alternatively you can use one of the ELM327 based ODB2 to either USB or bluetooth adapters along with the Forscan to read the codes. Once you have the code(s) you can then look at the area indicated by the code.
It may be a bad sensor, a broken wire, somehow a reluctor ring went bad, if you recently had bearings replaced they may have been installed backwards (as some bearings have the ABS ring integrated with them), or in worst case an issue with the ABS or traction control modules. Until you pull the codes everything else is just guessing.