I bought my 2015 xlt used with only one key and no card in the manual. Texted my service manager the VIN and he was able to text me the factory code. It might be worth a shot to call and see if they will help you over the phone for free.

 

I recently tried a youtube method using both keys going to the on position. Did not work. Hopefully, with nothing to lose, I then started the truck and let it run a few seconds. Followed that with the second key. As soon as I got to "On", the code appeared.