Can multiple Gen 3s share a fob?

Short, simple answer.....nope.

Posted via the PriusChat mobile app.

 

The seed process installs a vehicle ID in the fob. Only one id at a time.

You can remove a fob from the list on the car and register other fobs. That removed fob still has the original vehicle ID in it and can be registered again with the same vehicle without requiring the seed process.

So the real question becomes, what sets the vehicle ID? I don't see anything preventing multiple cars having the same ID. Except every car is initialized with a unique ID, and we don't know how that happens. It's probably a process similar to storing the VIN, which can be done with Techstream (and a seed).

Assuming you somehow got two vehicles with the same ID, there would be a problem with the rotating sequence code between the fob and the car. Each time a fob interacts with the car, a sequence code gets incremented. If an interaction is recorded electronically, a replay of it wouldn't work because the recorded sequence code would be out of date. But the sequence code process has to be able to handle pressing a button on the fob when the car isn't in range. The code in the fob obviously can get ahead of the car value, but not behind. So long as the fob sequence code didn't get too far ahead of the one in the unused car it would seem to all work.

Exercise for the adventurous... Set the same VIN in two cars. Try registering the same fob to both. You'll need quite a few seeds to accomplish this. The Toyota seed distribution system likely isn't going to be happy with so many, so you'll need to use a non-Toyota seed lookup process. The result of the exercise will probably demonstrate that the VIN is not the source of the vehicle ID, and that it's something different. Oh well...