Just an FYI...I didn't think this was possible but it turns out that you can program a key fob to lock/unlock 2 different cars.

We happen to have a 2007 G35 Sedan and a 2007 G35 Sport Sedan and I brought in one of our 3 key fobs for the Sedan to have them reprogram it for the Sport Sedan and lo and behold it now works BOTH cars! I know it doesn't make sense but it really does. I'm not sure how confident that makes me feel in the security aspect of these key fobs but just thought I'd pass it along in case anyone wanted to know if it is possible.

 

My 03 coupe fob also works on my 02 xterra. It's a fairly rare occurrence though I believe

 

You program the car to match the key so there is really no limit to how many cars it will unlock.The key is just a transmitter, it doesn't know what its connected to.

 

But its not supposed to work on 2 different cars at the same time

 

Says who? The key is a dumb device. Think of it like a TV remote, if you had 10 Samsung TVs (all different models) in your living room, when you hit Up channel on the remote it will change all of them. If all of your neighbors set their garage doors to the same channel, one remote would open all the doors. So it is with the key, if all the cars are set to know the same key, then the key will control all of them.

 

So what your saying is every key fob for every 2002-2006 g35,350z,Altima,maxima,xterra etc etc (they all use the same exact fob) works on every single car? No...just no. It's really rare to find a fob that will unlock multiple cars...if they all worked on all cars what would be the point in locking your car?

 

Yes and No. You have to go through a programming process in the car for it to recognize a specific key. If you do the same programming on multiple cars with the same key THEN they will all work with a single key.

 

But the fob is only supposed to pair with one code and every car has a different code (well not every car but there are alot of codes so the chances of them having the same code are pretty slim) that's the whole purpose of the key fob is to work specifically with one car. Like you said the fob is just a transmitter but it pairs with the specific code of the car you're programming it to and can only pair with one code at a time. Programming it to another car clears the code that was previously programmed

 

Not correct. The fob gets no programming on it. There is no two-way communication so there is no code to clear on the key. The fob has a set code that it tells the car, the car then registers that fob's code. If you do the same procedure on multiple cars they will all work with a single fob. I am not aware of any car manufacturer that is an exception to this. I had multiple Fords using the same fobs before, I just programmed them both to the same fobs.

 

Well that goes against everything I've ever been told but maybe you're right I don't know I'm just saying I have an oem fob for my car and an eBay fob for my xterra and they both work for both cars but I didn't program them to both cars I programmed each one to each car

 

Then both of your keys use the same code. There is a finite number of codes so any given key will open any car with was coded to the same key code. Because there are so many codes, the odds of any two being together that are coded the same is very rare. I can't even imagine the odds of you ending up with two keys that are coded the same, you should buy lotto tickets. If you bought another fob, the odds are that it will be coded differently and will only work with one car unless you coded both cars to it.

 

cool now i will program my titan to work on my G35s fob.... one fob 2 keys if only i could change the key too that would make things much easier

 

Be careful doing that. When I had both of my cars coded to the same fob I would accidently unlock both cars and drive away leaving one car unlocked.

 

^ in that case the other car will automatically lock itself after a few seconds as long as the door was not opened, at least thats the case with both my infiniti's

 

I never noticed that my G did that. My Fords didn't, they would remain unlocked so I would unlock both cars, open the door of the car I was going to drive and then hit the lock key to lock the other car. More than once I drove off with an unlocked car in the driveway so I bought another FOB and reset one of the cars so they were on their own fobs again.