I've heard a common cause of the abs light coming on is the wheel sensors aren't picking up a signal (usually from the front wheels). Blasting the inside of the rims with a high pressure water jet will often remove the brake dust and road debris to restore normal function.
Having any important warning light (like the abs or check engine) come on is alarming to say the least. It would be nice if they could somehow set up the lights in a tiered or importance ranking. Such as this one means "stop immediately and check this out"
or "this isn't critical, check it when you can
" kind of lights.
I had the check engine light come on in our old Ford van loaded to the gills towing heavy up the Baker Grade in 100+ degree heat on the first day of a 2-week vacation and about freaked out. Pulled over and checked everything -- all good as far as I could see. Got home w/o incident and called the Ford dealer, and the service dept said "Oh, that could be because your gas cap was loose".......
I'm sorry but I don't want to be pulling over on the freeway to investigate a warning light because my gas cap might be loose.
I guess there's more than one reason why they're referred to as "idiot lights". You don't want your warning lights to be a Boy Who Cried Wolf situation......