Well like mr.crx said, 17 is speed sensor. It could be several different things. Your speed sensor in the trans has a little gear on it, that might have broken a couple of teeth off that gear, the cable might have seized up and broke, the actual cluster might be bad, or the clip the holds the cable to the cluster become's brittle cause of heat and soforth cause it's plastic and broken off adn the cable just slipped out. I hope that expain's it a little better.