The original owners would have set up this code. Check your manual to see if they jotted it down there. Otherwise check with Ford or the radio maker. I had this problem and couldn't get the code. The shops wanted to pull my radio at much cost so I just left radio on and in a week or so it just started working again. If this is the case check your manual and change to code you will know.
RhodaRose, October 2012