Hi everyone, 

I got the 2009 GT-R, it threw some ECU codes P0797, P0840, and transmission codes  P0840, P0797, and went into limp, only 1,3,5 and reverse, and speed limited to 30km/h,

I cleared the codes, worked fine for about 10 minutes then popped the codes again, 

But the brain twister, I was taking it to the workshop, so I cleared the codes to allow me to drive it, drove it to the workshop that's about 40 minutes away, perfect drive, no codes, 

Then went out with the technician, I drove while he monitored live data on his own scanner, I got to 240km/h in an attempt to stress and force the codes to pop, nothing, even love data was perfect,

Drove it around all day today, nothing at all, 

Now, I consulted with the GT-R specific workshop head at Nissan, he said I need to replace the Oil pressure sensor located inside the transmission itself, and some O rings and seals, and maybe a solenoid or two, 

However, he also said that since the codes disappeared, it may have been an air bubble that just passed through naturally, 

I'm honestly lost, do I replace them or just wing it and hope for the best ? 

Note that the car has less than 39,000 km on the odo "real", and has been serviced strictly with OEM parts I personally ordered from Nissan Japan, not dealers or aftermarket, even the transmission oil, I bought that 20L drum from Nissan amd did an oil change about a year ago "less than 1,000km so far", 

The car is kept at stock, no tuning or modifications whatsoever have ever been done on it, 

Anyone had the same experience, and what did you do ? 

I attached a picture of the codes I got using my cobb

Thanks in advance for the help 

Edit, live data, not love "autocorrect" 

Err, you did 240kph on a public road?

Yes, I've even done a full on top speed run with it, I live in a country where traffic laws are merely a suggestion, like they're there, you may or may not abide by them, unless you're busted, and police cars max out at 100 or 120km/h, so it's ok 😁

What country is that?

I'm no R35 expert but I do believe they have a 180kph speed limiter. So, your car must have *something* done to it in order to reach that stupid speed on a public road. 

Some do depending on the country, mine doesn't, I've gotten it to 280km/h twice,

But I'm responsible, only when I'm alone in the car, only on highways I know very well and the road is empty 

The ones sold in Japan are limited to 180, but all others sold in US, EU and Middle East have the limiters removed and top up at 315km/h, unless a specific market or country requires a limiter 

I don't have much specific information on these boxes or there errors, other than to say that they are prone to issues, particularly when pushing more power than standard (I know you said yours is un-modified).

Here in Australia we do have some very experienced workshops like Just Jap who look after a lot of the R35 Rally cars, and Dobsons in NZ likewise, but I'm not sure how you will get good support elsewhere other than through Nissan....

Thanks for the response Duncan, I spoke to Nissan, first he said that I need to change sensors, seals, O rings and solenoids within the valve body, but later said it could've been an air bubble that just passed through,

I just want to know if anyone had the same experience and what they did, because I don't want to change the parts if there's no need because it's gonna cost a lot "already got a quote", and I don't want to risk leaving it for the thing to go haywire when I least expect it 

Can you just do a simple fluid flush and see if that helps? Duncan and I were both talking the other day about this job and it can bring some pretty positive results.

I've seen someone in the US buya busted GTR at auction, it was doing the same as yours, except codes were coming back.

They did the things suggested and it fixed it all.

My understanding is if you do have an issue, not fixing it and it coming or going can lead to exploded internals as it can end up stuck in more than one gear at a time.

Take the above with a grain of salt; I've had zero first hand experience with an R35.