ABS light @ high speeds

When I reach the speed of 90 and higher my (ABS) warning light on the dash will come on. Then it won't go out until I restart my truck and give it about 30 seconds. Is there a reason for this?

Anybody have any ideas why?

what code, off hand check for:
bearing going bad in front, jack up and wiggle top and bottom should have no play.
one or more tires worn more than others
low tire pressure in one or more tire