Even with a dead battery in your fob, you are still be able to start the car!

 

This happened to me the past couple of days. The car is only 3 months old (GX460) and so I took it to the dealers with the key fob that I normally use as well as the spare key fob that has never been used. They replaced the battery in one of them and guess what? It still says "key not detected". Tried to do the reset routine and it still doesn't work. The car is at the dealers and they are going to look at it on Monday as they are baffled as well.