I have not had any problem programming any 2 of the four keys I have. Forscan says you can program more than two but it only stores two. Guess I will have to go the clone path for the third key. Something funny on my truck, or Forscan.

 

Not sure about with using Forskin but the key programming capability of the truck can be turned on or off by NGS or WDS
So, someone cannot just borrow your fleet truck and go have another key made if you turn that function off
it's the key programming enable pid IIRR
Make sure that one is on

 

In forscan key programming window there is a toggle for spare key, enable / disable. It is set to enable. That is all I have come across.

 

Well, I managed to get all four keys working. All start the truck.
For the first two main keys I used Forscan erase and program. Two keys required, can not be clones. I used the Ford key and the failed clone from Lowes. It is an Ilco key.
The others are a pair I bought on Amazon.

The other two I used the addon method listed in the manual.

Put key in, turn on, wait for non blinking theft light to go off.
Quickly, repeat with other working key.
When I turned on third unprogrammed key the theft light stayed on for 3 seconds and turned off. I turned off key and left in inserted, and off, for 30 seconds.
When I had previously tried this method the theft key flashed upon inserting third key.

I had three keys working at this point. A normal man would have stopped at this point. But Not Me... Took the two main keys an repeated the adding key process.
Four working keys. Not sure why, but I do remember the theft light flashing when i stuck the 3rd key in on previous attempts.. But I got it.
Thanks!
Brian