When I got my Fiesta, it came with two "Admin" keys.
So if the display shows that more than one key is Admin - then that other key has to be present in order to allow changes to any keys or to introduce any key into the system.
To find that out go to MENU > Vehicle > My Key and review the keys it's thinks it should have. If it shows two Admin keys but only one in your hand, then you will have to see a dealership to restore a proper Admin key so you can release or change that third one.
To the best on my knowledge the Fiestas require 2 Admin keys for any changes to key hierarchy and functions allowed can be performed.
In a 2015 in the OM it starts on or about page 50
Further Advice:
- When you buy a car used.
- Best to locate ALL the keys for the vehicle - I know it's expected; during the sale to find you may need to let the seller be acknowledged that the previous owner has "issues". The previous owner may not have surrendered all the keys to the vehicle when ownership and possession was changed.
- So, if this is a "Take it or leave it" type of sale - it might be better to simply purchase the car and let the Title Taxes Insurance - plates ; everything you need to make that car yours (If you still want it) to clear and protect you - then take the step and simply bite the bullet and take the car into a dealership for a new issued key to replace any set that was left or lost by the previous owner. Get your car secured by the best and efficient means possible to ease you, your vehicle and and underwriters mind - it may be expensive, but this may be the only way to protect you - even when dealerships and or public sales - clear the title and you finance it. There may be scruples over the vehicle you cannot control- but you can control who has access to it.
- I'm not a lawyer so take this advice with a grain of salt - even if ALL the car keys are present - even then you should also think about securing a spare key for if ever there is an instance where you need to recover the vehicle due to a prank, theft, carelessness or OUIL-condition causing the vehicle to be impounded - you may never get the set of original keys you bought the car back due to forfeitures. So the spare set you have in a safe zone - may be the only method you can use to get your vehicle back and also show proof of ownership.