2002 Buick Century anti-lock service light and off trac lig

I have had this happen twice. Both times it was caused by the wiring on my front wheel bearings (that carries the ABS signalling back to the computer from the wheel) having broken at the connector. To know which one is failing I had to put the car on a scanner. My local Autozone did it for me for free, and I bought the replacement bearing hubs there. They run about $100 - $150. To replace them is fairly straightforward but I had to borrow a special deepset socket from a mechanic friend to remove the AXLE spline nut. Whole repair for each side was about 45min.