I just bought used 2006 G35x, and called locksmith to get another fob key. He's a guy with a lot of experience, and he noticed that my car starts even without a key or fob remote. He tried to "clear all keys" & program everything, but it still didn't resolve the issue.
So I think previous owner done something to this car, but no-one knows what he did...
Locksmith suggest to get a new body control module & program it.
Is this correct? Very hard to get this BCM out of the car and replace.
Please help me if you know where I can look to resolve this issue. Thanks.

 

Any chance your car has an aftermarket remote starter installed?

 

I don't know. Where do I need to look for this remote start? Is there a way to disable it?
I bought my G35 from a dealer, and he doesn't have previous owner information (to ask about remote start). He only gave me the key, and I duplicated it to have another.

 

Sounds like the previous owner had the car tuned and deleted the NATS stuff. Dealership can flash it all back to stock but if it is tuned then it's probably running a lot better than it would on a stock tune.

 

Thank you for the reply. Is there a way to fix this NATS without a dealer? (I'm sure they will charge me a lot of $)
Maybe not related, but I got a BCM unit from a junkyard, and I practiced on replacement. Should I try to replace the BCM, and program it to accept only my new keys?

 

It's not as simple as just plugging it in. The ECM and BCM needs to be paired, then the BCM needs to be programmed to accept your keys.

Dealership Consult-II/III

Uprev tune

Nissan Datascan 2

Those are your options.

IF you do actually have an uprev tune then I think the easiest/cheapest option would be to buy an Uprev cable and pay someone to etune/reflash your car and re-enable the NATS stuff.

@seymore4 can chime in and give correct info about the UpRev stuff.

 

Check for map switching, that will tell you if its been Uprev flashed or not.

 

Thanks. After reading more in the forum, I decided that there must be a hidden original key somewhere. I found it under passenger seat under 2 layers of carpet.
Now the car doesn't start without a key
Something else I noticed, the service key is able to open the door, but any other original key is not.
Nothing is wrong with mechanic of the door, because remote is working fine + service key able to lock/unlock.
What can be the reason that they car key is not able to open the door?

 

Thanks for the update. Good find on the hidden key! What a strange thing to do. Also, your locksmith must not have been able to "clear all keys" or that would have put an end to it.

Your '06 has a "push and turn" ignition, right? Have you tried any of the physical keys in that switch (with no fob in the car)? One possible scenario could be that the original owner misplaced both original fobs, including the physical keys. Then bought a replacement fob and changed the door lock cylinder to match that new physical key. But instead of also changing the ignition key cylinder (expensive) they stashed a fob and programmed the car to start from that one... Just a theory.

 

My locksmith said he did run the "clear all keys". Maybe he made a mistake. I was also reading the original keys can always start the car even if you program new ones (but I don't know if this is true).
Yes, my car have "push to turn" (G35 2006): The "service key" without any chip is able to open the door, but the ones with chip are not able to open. So strange... I would think this need to be the other way around.
I think I need to call the locksmith again. He may setup something wrong with BCM.

 

I think what he was asking is if you have the intelligent key system or not.

Do you have to put your key into the key slot to start the car or is there a twist **** on the steering column and you can leave your keys in your pocket.

 

Um, yeah, er... I read this whole thread as if he's talking about discovering an iKey fob hidden under the passenger seat which was allowing the car to be started with no other key or fob present. I could easily have misunderstood the entire story.

So OP: does your car have the iKey system with a push and twist ignition switch? Or the more standard old-school ignition key slot?