Why is the speedometer not working in my 1998 Cadillac Concours Deville?

Last week my speedometer and tachometer quit working, also my Traction Control Light as well as my Check Engine light are illuminated, this all started at the same time. My car acts like the traction control is engaged. Can someone PLEASE give me some istance on this. Also, I took it to AutoZone and they can't get any codes.