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2014 Q50S Hybrid AWD Transmission Problem (Code: P2859)

23K views 38 replies 12 participants last post by  deniseveremey 
#1 ·
Hello!

I have finally had the uninvited CEL on my 2014 Q50S Hybrid AWD. It started about a week ago. I was in school and returned to my car on a cold winter day in the evening. When I started my car, a bunch of lights came on including the front collision warning light, the brake warning light, and the direct response hybrid system warning light. The car started fine and I let the battery charge a little, but when I put it in drive, the car made a persistent cluttering noise as I barely hit the gas and the car would barely move. I put the car back in park and turned it off. I waited a few minutes before turning it back on and the car started as usual. This time, the direct response hybrid system warning light remained on and the brake warning light remained on but I was able to drive the car back home with no issues. As I got near my house, the CEL came on as well. I parked the car and disconnected the battery, hoping that it was just some electronic malfunction that would go away as I have seen posts about how winter weather screws up the electronics on the hybrid models. I drove the car again yesterday and the CEL is still on along with the direct response hybrid system warning light. I took the car to Autozone to have the code read and the only code I got was P2859 (Clutch A Pressure Disengagement Performance).

I thought maybe it has to do with the battery or the electric drivetrain because I have posted here about how there tends to be a jerk in my car as I near a stop with light to medium braking but that jerk never occurs if I brake hard to a complete stop. But now I am convinced there is something wrong with the transmission. My car is not under any warranty but I don't want to start throwing parts at my car until something works. I'm worried that I may have to swap out the transmission but that is also very expensive. I couldn't find anything related to P2859 for the Q50 Hybrid but have found some stuff on Nissan Sentras and Versas about the CVT transmission having issues. I understand that my particular model doesn't have a torque converter and it's not a CVT so I really can't figure out what I should do next.

If anyone has experienced anything similar, I would love to get some help. This car is my baby and even though I dislike the hybrid system on this car, I love the car.
 
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#2 ·
Well first your car should be under warranty as the drive-train gets a 72 months or 70,000 miles so double check that, it's possible this was caused by a low charge level on your battery but I'd say
check your fluid level on the transmission as the 7-speed Infiniti uses is pretty dang reliable.

Turning off the battery likely won't due anything as those codes are typically stored long-term and need to be cleared by a tech, call the dealership and have it towed there after your
confirmed your still under warranty.
 
#3 ·
The P2859 DTC is thrown when the transmission fails to properly disengage when coming to a stop. It could be a low transmission fluid level as BHC said. If not, you are probably looking at a clutch replacement.
 
#4 ·
There are have been a number of threads the last couple years on here about all manner of issues lighting up the dash on a 2014-2015 hybrid. Almost all of them were a result of a bad 12v battery (not the hybrid battery). You have a 2014 model and if that battery hasn't been replaced yet, then it is due to be replaced and could very well be what is leading to the odd issues you are encountering.

All that aside, I would bring it to the dealership to get a proper diagnosis done.
 
#6 ·
Power-train warranty is 6 years for the 3.7L... why don't you bring it in?
 
#11 ·
Thanks for all the comments!

So I ended up taking the car to the dealership and they found two codes: P2859 and P0806. According to them, there is a small leak at the bottom of the bell housing, which means there is some leakage of fluid. They stated that the transmission fluid is very dark and burnt. My guess is that is has never been changed. I bought the car used and it is out of warranty due to the mileage. They told me I could "replace the clutch, pressure plate, flywheel, and transmission" for $15,000. I asked the Service Advisor if it would be more suitable to try a transmission flush. She said that I am better off not doing it. I have heard theories about how you should not change the transmission fluid because the transmission gets accustomed to the dirty fluid and I may experience a jerky transmission if I do change the fluid. I am definitely not going to replace the transmission (unless I have to in which case I will be searching on eBay for a used transmission) or I can try a transmission flush and pray that it works. What do you guys think? They were nice enough to get rid of the CEL and the direct response hybrid system warning light.

When I saw the million lights pop up on my dash, I freaked out. But to answer a post above, the 12V battery was replaced under a recall last year. I think it was just because of it being so cold that day and I may experience that again as it has been quite chilly in Central VA today.

When they quoted me the $15,000, I literally laughed my ass off as I walked out of the dealership.
 
#13 · (Edited)
Drain only, Never flush the system. It will likely kill your transmission given how you've described the transmission. How many miles are on your car??? Because your fluids shouldn' be in that bad of shape than unless it was contaminated due to a faulty seal somewhere.

The transmission is a closed system and designed to last the life of the car without any service or it's fluids replaced, most have no issues going 180-200K miles on those things without any issue. That said I'm part of the "Do a fluid change around 60-70K mile mark" as those fluids can and will breakdown over time.


OK, so why no warranty?
Out of warranty due to the mileage as he said, so I assume he was passed the 110,000 kilometres or 68-70K Miles mark.
 
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#14 ·
I've crossed the 100k mark. I have a long commute. I'm thinking the old fluid with the cold weather is making the fluid thick so it may be causing me problems. I'll look into draining the fluid and replacing it with new fluid. Any recommendations besides the Matic-S by Nissan?
 
#15 ·
Ah that makes sense, it could very well be the cold weather and thicker fluid increasing pressure and squeezing it out past the seals even if it's not a
perfect fix if the car becomes driveable after that it would be $200 well spent. Then just drive it into the dirt after that.

If you do decide to swap out the transmission just remember to go to a 3rd party seller, plenty of them out there can be bought
for under $5000 and have lower mileage. Then it would just be labor to remove/replace either way you should come out at least
half of what Nissan is quoting you for this job.
 
#16 ·
Yeah. Sad to see such a nice car have these issues. Won't be buying an Infiniti Hybrid anytime soon. Although I was able to get 9 qts of fluid from a local Nissan dealer for $75. Hopefully it fixes the issue or else I may look at transmissions on eBay. They seem to be going for around $1,000.
 
#19 ·
If your transmission color is burnt and they see metallic bits in it they wouldn't even pull the transmission to know there was some serious damage.
 
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#20 ·
I was thinking of doing a drain and fill. I'm worried if I do a full flush, I may end up having more problems like slippage etc.

This was the link I was looking at. I'm guessing the procedure is going to be the same in my car. I will see if I can do it next weekend.



Any other links relevant to the Hybrid will be much appreciated.
 
#21 ·
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#23 ·
UPDATE:

I was finally able to get under the car and swap out the transmission fluid. The fluid was certainly black. The car is driving like it was before but I'm unsure if the warning lights have gone away because of the fluid change or because the weather has warmed up the past couple of days. Either way, we have a lot of cold and rainy weather this week so I hope the car stays this way. I will keep you all posted! Thanks for the all the replies!

Also, seems like the techs at Infiniti didn't even get under the car. I think they only got a bit of fluid from the overflow bolt and claimed I needed a new transmission. I don't know where they got the whole "leak from the bell housing" bullshit. I will be speaking to the reps at Infiniti because their advice didn't look very convincing when I got under the car. I did not see any leaks at all.
 
#24 ·
I have got my reservations about taking my car to a dealer but I would say its also possible they cleaned or wiped off the areas that had been leaking. If so you can use this to take note where specifically the leak should be coming from and or how much/often it is leaking. This is an issue I do not want to come across, if a fluid change can somehow fix the ailments its certainly better than the alternative.
 
#26 ·
ANOTHER UPDATE:

Things have gone from good to bad. My car has been running fine for the past two weeks but has started acting up again and I’m hearing some weird noise having to do with the EV mode as well.

A few days ago, I started the car and all the dreadful lights came on again. I drove the car home on gas only. The car did not even attempt to go into EV mode after the first attempt when I started the first few minutes of my drive. When I got home and turned the car off, I heard a nasty clunking noise from the front left side of the car. I only can repeat this sometimes when the car is not going into EV mode. Like today, the car ran fine even though the lights were on. But there have been times where I try to accelerate in EV mode but the car jerks and refuses to move, as if something is stopping it from moving. I can’t pinpoint what is going on. I tried having the CEL code read again today but this time, no code was registered. I also notice that my car was in like “half EV mode” where it tried to go into EV mode but couldn’t so it went back to gas.

I’ve attached some pictures to show you guys what I’m talking about. I doubt it’s the transmission anymore because in gas mode, the car runs perfectly fine.
 

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#27 ·
If you have just a generic $20-$50 scan tool it may not be able to pull the codes/errors that the Dash is reporting on, typically you need a high level scan tool to see all the errors are car can report on.
To me it sounds like the hybrid system isn't engaging when it try's to switch to EV mode, as Avedis indicated this is starting to look like your clutch has went bad.

Time to bring it in to a 3rd party shop that is known for working on Nissan/Infinti and have them take a look at it I'd say.
 
#28 ·
Cross traffic alert error, front collision warning error... What does this have to do with the transmission though? As I said before, the car runs great on some days but then acts up on other days. I just can't seem to figure it out. No wonder they dropped the Hybrid models because they obviously were making **** cars. Debating on trading it in but I won't get jack for it with all the warning lights being on like that. Or I could invest in a used transmission but will that really fix the problem?
 
#29 ·
My hybrid has been trouble free.

Having said that I think you should follow the recommendations here and get it to a well qualified repair facility and get some useful information. It will be much easier for you to make a decision knowing all of the facts.
 
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#32 · (Edited)
Yes, the 12V battery was replaced under a recall last year. I'm dreading that it may be the transmission because when the car does not go into EV mode and when I turn the engine off, the car makes a nasty clunking noise. The noise is nonexistent when the car is able to switch back and forth between EV and gas like normal. It could also be the inverter according to the dealer but hard to pinpoint what exactly is going on. Tough to find a mechanic who knows Nissans/Infinitis well around here, especially the hybrid models.

The only codes I've gotten include P0806 (Clutch Position Sensor Malfunction) and P2859 (Clutch A Disengagement Performance).

I should also mention that the nasty jerk on light braking as the car nears a stop that I mentioned in my first post has gone away ever since I changed the transmission fluid. So I really have no clue what is going on.
 
#35 ·
Wow everything from the weird lights to the nasty jerk on light braking to the ev/gas incompatibility to the p2859 p0806 code is exactly what I’m going through right now I know it’s been some time now but can you let me know what solution you found if any?
 
#36 ·
What year, tryin and mileage is your Q50?

Has the 12v battery ever been replaced?
 
#39 ·
Has anyone found a fix to this problem. I’m having the same exact problem. I have replaced my hybrid battery with a refurbished one cause the dealership led me that way. Battery was warranties and they came out and replaced it again cause everything remained the same once changed. Now we know it wasn’t the hybrid battery.
 
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