ABS CODES C1234 Questions

When I Plugged In An Obd2 Scanner Into My Vehicule (ford Focus 2003 Zts 2.0l, Vin On Demand) A Few Months Ago, I Got A C1234 (speed Wheel Rf...

I Have A 2000 Ford Expedition And It Has Some Problems ....when Im Driving The Brake Sometimes Is Pushed All The Way In And Sometimes When I...