take it to the dealer. they can tell right away what sensor is bad. mine was the passenger front that went. cant remember what it cost but it wasn't to bad.
and it beats trying to reach it yourself.
Mine has been coming on and off for a while, and of course when I go to the dealer it doesn't do it and they cant find anything, (off topic same thing with the svc 4 wheel drive)
This problem has been worked on 4 times throughout ownership. Service Manager stated it will be repaired for no charge since it was last serviced 4/26/06. I hope it is corrected. Mick