If scan shows error with Speed Sensor does that mean a wheel hub replacement

What is your question?

The ABS service Advance Track light comes on but goes off and sometime (days) later it may come on a few sec and go off. Was in to have brakes checked, all in good condition they said, then he put a scan on it and the only thing that came up was about the speed sensor. I was then told it needs a wheel bearing on the front right. I had a situation when I applied brakes hard, the ABS kicked in and made a loud noise under car. I had asked the FORD garage about the warning, and they said don't need to be concerned about it if it don't stay on. I wanted the brakes checked cause of that CRUNCH...scared me not knowing what it was. Brakes were good. then hooked up scan and the error came up for the speed sensor. He explained what the sensor does, but then inside he said a wheel bearing, the lady called for the part; stated the WHOLE HUB needed to be replaced could not just get a wheel bearing? When asked about an estimate was told 307 for the part, 90 for one hour labor???

What makes this problem better or worse?

Sometimes the ABS SERVICE ADVANCE TRAK came on at start up, but not always One day it came on going through the car wash

How long has your 2010 Mercury Milan had this problem?

maybe 5 months before the CRUNCH sound Was told that was ABS kicking in