# Immobilizer hassles on R34 GTR



## danox574 (Jun 1, 2008)

I have one working key for me R34 GTR and I'm attempting to make more. I have the blanks, and my car arrived originally with a Apexi Power FC and hand commander. My dealer is willing to assist me with programming, but he says he needs a factory ECU and a working key to talk to the immobilizer system. According to both the dealer and the alarm guy who got me started on this, the immobilizer system is separate from the ECU, but electronically programmed through the ECU, so I went looking for a factory ECU.

Build date for my car by fast was 9910. When I put part code #22611 (the ECU) into Fast, I receive two different part numbers back:

23710-AA300 (9901 to 9910)
23710-AA301 (9910 to 0010)

According to FAST, when I do an alternative part number search, I get the following:

For 23710-AA300:
2371M-AA300 - ICA code 2
2371M-AA301 - ICA code 2
2371C-AA301 - ICA code 7

For 23710-AA301:
2371M-AA301 - ICA code 2
2371C-AA301 - ICA code 7

ICA codes are listed at the bottom of the screen as 'ICA CODE, 2,3: YES, 5-9:SET CONDITION'. When I clicked on the 'Set Alternation' button under ICA code 2 parts, nothing happens, but under code 7 parts, I am taken to a screen with a list of parts that includes two mounting brackets and four screws.

From this, I am deducing that if I use part 2371C-AA301, it requires separate mounting hardware.

So, I obtained a brand new 2371C-AA301 Nissan remanufactured ECU, assuming that I could put it in, drive it to the dealer, and have them access the ECU with a Consult II or higher and a NATS 2.0 card and then tell the immobilizer system to accept these new keys. The dealer has agreed that this should be doable.

Problem is -- when you put in the 2371C-AA301 ECU, none of the keys work. The light comes on the dashboard indicating a key that is not passing the immobilizer check. The immobilizer is rejecting the original key that is programmed into it with the 2371C-AA301 ECU attached, but as soon as I put the Apexi FC Pro back on, that one key works again. The key understanding I've been able to get from the web is that the immobilizer has it's own memory, and once it's been told that it should accept a key, it tells the ECU that fuel delivery is allowed (and the red dash light goes out). Given this general understanding, I have no idea why the 2371C-AA301 ECU, listed by fast as an alternative part # for the original ECU, makes the immobilizer suddenly reject keys, but the Apexi allows them.

(And why in the world is there not an option in the PowerFC to ignore this immobilizer input?)

I'm going to pack up the whole mess and take it to the dealer on Tuesday and see what they can figure out for me. If the ECU won't start the car but they can at least talk to it, maybe they can program the immobilizer.

Any knowledge or advice would be appreciated.

Thanks,

-Dan


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## StretchGSK (Oct 24, 2006)

I find this a bit odd as I was told by several tuners as well as Nissan that if you replaced the factory ECU with a PFC or similar you lost all Immobilizer functionality???
Have you had a look at the R34 Service Manual supplement 1.pdf


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## danox574 (Jun 1, 2008)

I have heard the same thing, but I can confirm that this isn't the case. Keys with chips and also Nismo 10 point keys cut to the lock cylinder do not start the car with the Apexi, only the one I received with it will. The others turn on that red LED in the dashboard and fuel delivery is cut. That did not surprise me, but the immobilizer suddenly rejecting the previously working key with a Nissan ECU did take me by surprise.

When we installed an alarm, we found the immobilizer system -- it was no doubt a seperate piece of hardware from the ECU -- and according to Nissan documentation, the immobilizer system is spoken to through the ECU, but is not part of it. Some found Nissan docs also say that a new ECU requires complete reprogramming of all of the keys, but it was not a Skyline specific document and the NATS version could be different.

The Apexi is designed to be a drop in replacement for the factory ECU, so my guess now is if I drive the car in to the dealer on the Apexi, swap the ECU, have them hook up a Consult II or greater with NATS card to the car, reprogram the immobilizer from scratch by initializing the whole thing, then putting the apexi back, everything will fire up, but my fear is if I don't track down some real-world info, I'm going to be towing the car home with nothing working if we screw it up. There's no way that putting an Apexi in would require immobilizer work or people would have posted about it. Yet, the docs do say an ECU change requires NATS init. Perhaps the Apexi looks like no ECU or a generic ECU but the immobilizer looks for a specific ECU and the one I acquired is advertising itself as the wrong one.


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## Mini-E (Feb 29, 2008)

Im also looking at getting a spare key for my jdm r34 gtr.
How do i go about doing this?

Its currently got a standard ecu (but thats now being replaced with an apexi pfc). If i get an origional spare key and bring it to nissan can they reprogramme it to work with my car (although its a jap import). Its got a five digit number attached to the key i have, would this be some type of code to reprogramme a new key. 

Any help appreciated, i dont trust myself with only one key for my gt-r.


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## MartinC (Jan 1, 2006)

Maybe the Nissan consult will re-program the keys with the apexi unit in place.

The key would never work with a new ecu, they need to be coded.

I would have to try it to be sure though!!


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## danox574 (Jun 1, 2008)

After going through this, I can tell you that any dealership with a consult that will talk to your car and a NATS 2.0 card will be able to program additional keys for a 1999. In the US, they had no problem with the JDM car. However, it must be done with a factory ECU -- we put the consult on both the Apexi FC and the original, and it would only program with the original ECU. The FC doesn't even respond to the consult.

The part # is H0564-AA410, which is listed as a 'MASTER' key. Make sure master is in the part description, or you'll end up with a sub-key which has no chip inside it and cannot be programmed. (I made this mistake and wasted a lot of time and money). They are about 7,200Y. My dealer requried me to have them cut before I brought them to the dealership as they did not cut keys, and could only encode them if they were put in the ignition and turned on (this is part of the process).

I think you can program up to 3 keys.

Once you have both keys programmed, you can switch back and forth between an Apexi (and likely other aftermarket ECUs) and the original factory ECU for the car, but if you put in a different factory ECU, you will need to have the keys re-coded for it. 

I think the 5 digit code is likely irrelevant from the immobilizer standpoint, as the immobilizer system is programmed to accept whatever keys are thrown at it by actually reading the chip, not by any code programming or numbers. Some Nissan immobilizers have a PIN # that is required to be entered before they can be reprogrammed, but my 1999 did not.

I was told that someone with a 2000 ECU tried to put it on a friend's 2002 NUR for whatever reason and found that the NATS system would not communicate, so there may be multiple revisions of NATS across JDM cars in the 99-02 stretch.


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## Mini-E (Feb 29, 2008)

Thanks, great info, goin to try my nissan dealer so. Where did you get your master key from, did you get it at your dealer or direct form japan?


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## danox574 (Jun 1, 2008)

mine came from a JDM part vendor by the part #, but there were also US keys that would have worked that I could have bought from the dealer. I was told a 2000 Maxima key, for example, had the proper length and type of chip and would have worked, but that key was actually about $82 and more expensive than the japanese one. If you just want a working key to throw in the drawer, your dealer may be able to give you an equivalent, but if you want the big red R, you'll need to use the JDM part resellers.

There's a guy on YJ selling keys for 4,780Y but they do not have the chip -- his description says he can get the chipped ones for 6,480Y but proxy bidders like Rinkya are not so good at making sure they speak to the seller, they are a bit too automated.


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