We own two Prii a 2017 (the DW) and a 2024 that I drive. These fobs are very bulky in the pants pocket. I don't feel pretty enough to carry a man bag. So I'm wondering if one fob can be programmed to two Prii. I've read some mixed info on this. The most promising was that the fob could be used to start/stop both vehicles but not operate the locks. No big. I add another key to my key ring. Has anyone tried this and failed or succeeded. We took the 2024 on a Christmas trip from DFW to the Phoenix area and it was fantastic! The 2017 was a bit under powered when loaded with all 4 of us plus luggage and Christmas presents, but the 2024 had plenty of power. I never lacked for power when passing. I added a hidden hitch and since we don't travel light I put a cargo basket on the back. It worked great!
A gen 4 Prius is most likely going to have a Key Fob code that works differently than a Gen5 Prius... Perhaps you could stash the Fobs in the vehicle and only carry around mechanical keys or an altervative security system? I know one Prius owner that had an RFID tag put in his hand so he never has to unlock doors in his house anymore, but he didn't have an implant for his Prius yet. Or just setup duplicate keys and fobs in the house in places where it's easy to grab/keep track of? Because clearly, once you leave the house you're only going to use one fob, right?
The gen4 and gen5 do use different key fobs. The gen4 uses the #2 style that was introduced in calendar year 2015. The gen5 uses the #3/#4 style that was introduced in calendar year 2019. Since they use different chips inside, I doubt they are compatible. (The years are when the fobs were introduced somewhere in the Toyota/Lexus lineup, not when they were introduced to the Prius.)
That is an idea. I could put the fobs in the car in a faraday bag and pull out the fob after I climb in. I'll have to think on this one. Is the inconvenience of the fob being big and bulky bigger than having to pull a fob out of a bag after climbing in. The fob in the bag also protects from thieves who drive around with scanners to dup fobs and steal vehicles.
