Try leaving it turned on and what you might find is that after 30 mins or so with it left on you may be able to re enter the code again,this is how Ford 6000 series radio's work,you get 3 attempt's at it then it locks out but it needs to be left on so you can have another go in half an hour,If your worried about leaving it switched on in your car take it out and pop it on a battery in your garage/front room then when it starts flashing again you will see it,Like I said this is the way Ford radios work so it might work yours