I have gone to nats system, c/u initialization, it doesn't ask for a code, but I do the c/u initialization, it says "Initialization complete according to operation manual. Perform key registration". At this point I insert a new key and it appears to work, but I can only program one key. If I try to program another, it erases the last key I programmed. I believe there is a 5 key limit to this vehicle, could this have something to do with only being able to register one key, or am I missing something?