I think that each time you start the procedure to program in a key fob, it erases all the stored key fobs. Because when I got my new key fob and programed it in, the key fob for the morano that I tryed a couple weeks earlier didn't work any more. You can program in a maximum of 4 different key fobs but I think they all have to be put in at the same time by pressing the lock button on the drivers lock/unlock switch and pressing a button on the key fob that you want to program in after you have already programed in the first. Then you can program in another (up to 4 total) by pressing the lock button again and then pressing a button on the other key fob. I could be wrong on all of this but I will find out when I recieve the next key fob that I am getting from ebay. I'll let you know.