Hi, I had this issue with my passo (key not opening door using door-button but starting engine) and was able to fix it through a series of steps available on YouTube for another Toyota vehicle on registering a new key fob. It involved a series of manual steps such as opening and closing the door, locking and unlocking etc. Try to search on YouTube... This was about 3 years ago so i don't remember the exact video or steps, sorry! BTW, my problem started after I changed the battery in my remote. Happened the first time but fortunately never again on subsequently battery changes. Good luck!