Ok I think I may have missed something earlier. Do you have an intelligent key system (push button start)? Or a traditional ignition that you put the key in every time?

 

Not push button start but you dont HAVE to insert key into ignition cylinder.

 

I could still be wrong (bad score for me in this thread) but I think all physical keys, including the one that lives in the i-key fob, have embedded chips which the car needs to have in its "register" to be able to turn the ignition. Part of anti-theft thing. Could be that the OP's BCM has lost it's key registration memory?

Our '05 and '06 Gs had i-keys and the ignition switch needed to be pressed in slightly (even with the key inserted) before it would turn. That's what I meant a couple posts ago...

 

Ok I'm not sure what you're saying, there are two ignitions systems used on these vehicles, first is a traditional ignition where you put the key into the hole and turn. The other is the Nissan intelligent key system that has a push button on the dash you use to start the vehicle.

You told me you

1. Don't have a push button
2. Don't have to insert the key

... That eliminates BOTH options?

Do you have some kind of aftermarket ignition or are you talking about a vehicle that's NOT a G35 sedan?

 

haha, sorry.

It is NOT push button. But, so long as the fob is inside the vehicle you do not have to insert into cylinder. Meaning, you can turn the ignition on without the key in the cylinder. I am not explaining well but does that help?

 

I had an '06X premium sedan and can confirm the intelligent key system was not push button but twist cylinder on steering column. Same is true on my '06 coupe. Intelligent key stays in my pocket, just twist and go. It is slotted so you can use the mechanical key if intelligent fob battery dies.

 

Yes, that's the first iteration of the i-key - with FOB in the car you can (slightly press and) turn the ignition - or - you can pull the mechanical key out of the i-key fob, insert key, slightly press, and turn. That slight press is the point where the car looks for the chip embedded in the physical key. And if it's not present you can't turn the ignition cylinder.

yzinger, do you have any other of the physical keys that came with the car?

 

so you are saying because the cr2025 battery in the FOB was not great it would not give the signal from the chip in key to the car?

I can accept that but really think it is dumb that the physical key will not override. What if you are at camp and the battery dies. Your car is stuck there??? I cant imagine that is the case.

05_SS - the car came with two FOBS (of course with 2 physical keys that slide into those FOBS)

 

Ok I guess I've never seen the early Intelligent Key systems then. Just trying to figure exactly what system you have.

Yes the battery in the fob needs to be able to transmit a strong enough signal to the BCM antenna in order for the vehicle to recognize you are actually in the vehicle. The transponder chip inside the key is the failsafe method and inserting the key into the ignition cylinder SHOULD work.

I have a feeling that your BCM has failed and needs to be reprogrammed (or worst case REPLACED) by the dealership OR the antenna has failed. Do both fobs not work?

EDIT: I haven't actually disassembled an i-key physical key but most manufacturers use a backup transponder in the physical key itself. You can also try holding the fob itself right next to the ignition cylinder to see if that helps make it work, typically the "low battery failsafe" for manufacturers.

 

both FOBS work in so much as they will lock/unlock etc...the damn car will not start. It points to a NATS issue but i have read over and over that is it is a NATS issues the FOBs wont lock/unlock etc..

 

Yeah it definitely sounds like NATS, maybe a failed BCM since that's where the programming is stored. Hopefully you can just get it reprogrammed at Nissan and not have to replace the BCM since they can be a little spendy but either way it looks like you're going to need to be towed to the Nissan dealership. I recommend installing the license plate tow hook yourself so the truck driver doesn't use frame hooks and damage something.

 

Have you tried the physical key from your other fob? Or if you have it, the "Valet Key"?

I think the NATS and I-Key systems are seperate so it might be possible that the FOBs work and the keys don't, though I'm not sure about that...

Each of these physical keys has an RFID chip embedded in their little plastic bits. This was meant to be the backup scheme in case your fob battery dies or the fob is for whatever reason unavailable. I do not think the NATS system is tied into the door lock, just the ignition - but I'd need to look that up too.

I also believe these RFID chips are unique to EVERY key so the BCM needs to have each of these chips in it's memory in order to release the ignition cylinder and allow you to turn it.

If none of your physical keys can turn the ignition it points to either a failure of the NATS scanning system or your BCM may need reprograming. Hopefully that's all it is.

 

OK, after a bit of service manual reading I would like to suggest you look at a few fuses...

The IPDM is located on the firewall behind the battery (not very handy) but fuse #77 in that box sends power directly to the NATS unit so it would be worth checking. (See pic 1 below)

There are 3 more fuses in the fuse block near the driver's left leg which are directly involved with the security system: #1, #18 and #19. (See pic 2)

Wouldn't it be great if this was a simple fuse issue?

 

twist the steering wheel as far as it will go then turn the key its a anti theft system