What numbers exactly on the back of the key FOB need to be identical in order for the new FOB to be compatible with my one existing one and my 2013 Prius? The FCC ID? IC # ? Or the other small number below those two? Thanks.
The IDs should be the same for all Gen 3 smart key fobs. You need Techstream or a Toyota dealer to program the new key to work in your car.
It's ready to be programmed, yes. I think the FCC ID is just the part model number plus some other digits.
For a Gen 3 with the remote air conditioning, the fob has an extra button. As far as I know, the FCC IDs are the same, as is the circuit board inside, there are just two versions of the front half of the plastic case, one without the extra hole and button. You just have to be sure you're ordering the version you want. If you're not buying new, be sure the seller says the fob is 'virginized'. Those will work, but they sell for more than just plain 'used' ones, which won't (unless you want to go through a whole ECU reseed on the car). -Chap
As I recall, the most common Gen3 fob has an FCC id of 14ACX. There are others, so it's important to check.
