no thats the secret.......
if your abs light is on. it can be on for a # of reasons, most common is a hub. then come bad wires.
you can jack up your car at each wheel and see if the hub is tight by trying to wiggle the wheel at the top, grab the threads and push pull, but softly, if it moves that hub could be bad, also take the plug off dab some di electric grease on the plug ends, put them on, take them off put back on, to work the grease in, while you are there check the wires for damage along the lca's. same goes for the rear hubs, same tests.
if all of your hubs feel tight (wiggle test) and your wires look ok, then its best to go get it scanned at a garage, yes they will charge you, but its better than throwing money at $130 hubs and it not being what wrong.
dont know what year your car is, but the newer cars seem to let the free scanner at auto zone read abs codes. they wont have the info for the code at auto zone but can and will give the code to you and you can look up the code on line.