Ford 2011 Econoline Owner's Manual page 84

Locks and Security
6. Turn the ignition to the 2 (lock) position, and remove the second key
from the ignition.
7. After three seconds but within 20 seconds of removing the previously
programmed coded key, insert the unprogrammed key (new/valet key)
into the ignition.
8. Turn the ignition from the 2 (lock) position to the 4 (on) position.
Keep the ignition in the 4 (on) position for at least one second.
9. Your new unprogrammed key is now programmed.
If the key has been successfully programmed it will start the vehicle's
engine and the theft indicator light will illuminate for three seconds and
then go out. If the key was not successfully programmed, it will not start
your vehicle's engine and the theft indicator light will flash on and off
rapidly. If failure repeats, bring your vehicle to your authorized dealer to
have the new key(s) programmed.
To program additional new unprogrammed key(s), repeat this procedure
from Step 1 for each additional key.
84
2011 Econoline (eco)
Owners Guide, 1st Printing
USA (fus)