P0846 DTC on my 2012 Nissan Versa SV 1.6

The Nissan Versa Tech Discussion forum is the place to discuss Versa performance modifications and maintenance.
BbNicholas@18
Posts: 3
Joined: Wed Nov 08, 2017 5:01 am
Car: 2012 Nissan Versa SV 1.6 with CVT

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Hello, I am new to the site. Hope to learn a lot from everyone.
I have a 2012 Nissan Versa SV 1.6 with 260k miles. VIN 3N1CN7AP2CL876680. I bought the car with 45,000 miles on it.
I have a check engine light that I had read and it corresponds to a P0846 error code " Transmission Fluid Pressure Sensor/Switch B Circuit Range/Performance.
I have not had a bit of trouble with this transmission. I change the engine oil every 6, 000 miles and it runs fine.

This is the problem that I am having; I did this three different times,
Time 1. With the car warmed up to normal operating temperature and starting from a complete stop, when I press on the gas pedal like normal and come up to a speed of 31mph, rpm goes up a little and the car shudders a little bit to get into the next gear, then it runs fine as I give it more gas.

The second time I did it, it did the same thing except at 32mph.

The third time I did it, it did the same thing except at about 33mph.

I thought the CVT did not require you to change the fluid. Apparantely, you do.With that said, I have never changed the fluid in the transmission so I am not sure if that has anything to do with the PO846 DTC. Everything is dry under the transmission/transaxle as far as I can see.

I do most of my own car repairs to the extent possible. I did put a shift solenoid in my brothers TH350 years ago but the CVT is something new.

It would be nice if I could just change the NS2 cvt fluid or a sensor and that clears the P0846 code so I don't have to pay thousands of dollars for a new CVT.
Can someone volunteer some of there expertise in helping fix this problem.
Any and all responses would be greatly appreciated.
Thanks


amc49
Posts: 1183
Joined: Mon Jun 19, 2017 7:24 pm
Car: '11 Nissan Versa
'17 Nissan Altima

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I am always at a total loss to explain how people who change engine oil regularly have so much trouble with maintenance on other like items. How one thinks trans oil never gets changed ever? How is that possible and I do not care WHAT the car maker has to say about it. People should be able to recognize all the little mini-scams the OEMs use to wreck vehicles early to then have to buy new cars.

If OP is lucky it may just be low on fluid or very dirty to mess the sensor up.

EdBwoy
Moderator
Posts: 3507
Joined: Tue Dec 25, 2012 12:47 am
Location: Indiana, USA
Contact:

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Welcome to NICOclub Bb.

I am not very conversant with Versas, but I know that nothing lasts forever. At 260k miles, that sensor might really have served it's job and might need replacement.

It's true that transmission oil in modern AT units might not break down as fast in normal driving conditions, but it's worth checking for condition it if you can. Check your owner's manual on maintenance recommendation.

On the code, I'd recommend you look at the AT section of the factory service manual (linked below) and go through the troubleshooting steps. I sure hope it's just the switch - those are pretty easy to replace, unless you have to drop the pan & valvebody. At which point a fluid change is inevitable.

Let us know how this progresses.

BbNicholas@18
Posts: 3
Joined: Wed Nov 08, 2017 5:01 am
Car: 2012 Nissan Versa SV 1.6 with CVT

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Well I decided to just bring the car to the dealer and let them just do a drain an fill of the transmission fluid since getting my hands on the "charging pipe set (KV-311039S0) seems a bit difficult. I have the procedure in alldatadiy.

In any event this is exactly what the dealer said when I told them what the car was doing, that I had a P0846 DTC, that I wanted them to drain out the old transmission fluid and put in new;

" We do not recommend a drain an fill on your transmission with 261,000 miles on it. Something may come loose in the transmission and cause further damage. If you want us to do a drain an fill you will have to sign off acknowledging We (the dealer) is not responsible if anything happens to your transmission when you drive away from the dealership."

Instead she (the service writer at the dealership) said that we can diagnose the problem for $108.00. The drain an fill would have been 219.00 so I said do the diagnosis.
3 hours later the dealership called me and said,

" The tech performed diagnosis and found DTC P0846-fluid pressure sensor B. Tech road tested the vehicle and found the Data Monitor Aux Box has slip-needs to have the transmission replaced-total being-$3545.38 to replace the CVT transmission. "

Admittedly, the car shudders a little bit at 31 mph or so as I said in my original post. Other that that its good.
At this point, do I go ahead an take the dealers word or get a second opinion or change the fluid myself per alldatadiy procuedure, check to see if the transmission fluid pressure sensor is good and go from there or what?

amc49
Posts: 1183
Joined: Mon Jun 19, 2017 7:24 pm
Car: '11 Nissan Versa
'17 Nissan Altima

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' Data Monitor Aux Box has slip'

They are telling you the chain is slipping on the drive pulleys, probably your shuddering.

The rest about signing off on old trans fluid change..........................the entire industry is going that way to scare people into new transmissions. It comes from oldschool non-CVT types driven way too long with no fluid changes then the owners freak out to want a fluid change when it is too late. The problem being that by then there is enough metallic particle in the fluid to then have it act partially as the clutch disc, and a fluid change at that point then removes that to have the trans slip horribly as soon as the fluid is changed. The shops quit doing that because owners blamed them when the trans went out all the way.

Pretty much the entire industry does not want to mess with minor internal details either, such as what I do, I have recovered transmissions that I was told had to be changed by simply readjusting a (non-adjustable) band or such that got out of range or changing solenoids to make the car then run for years longer with zero issues. They don't want to bother with things like that, in today's world it does not provide enough shop money and almost everybody steers toward the complete trans change now to get more cash. Nissan does no physical fixes in the field at all other than complete trans changes and makes sense since the thing that wears most in a CVT is the belts and pulleys and you have to bust them down to get to that anyway.

CVTs are super simple as compared to oldschool clutch pack trans but the flipside is that you only have that chain/pulley interface to get you home, once that is dead the rest of trans is as well. On older types often another gear would get you home and save the towtruck cost. It's in Nissan's best interests to keep CVT sounding super technical and all magic as well, it makes selling entire trans changes more edible than it would sound otherwise. A major reason why the trans dipstick disappeared and you have to jump over all the monkeys to change your own fluid nowadays, they took that away from you. You still have to change fluid the same way you ever did but they changed that up horribly to force more dealer work into the shops. Charging pipe set.......LOL, ridiculous. All that extra effort to save the price of a dipstick and fill tube to give it to the CEO in a bonus for taking away more self-done work from owners to give it to dealers.
Last edited by amc49 on Tue Nov 14, 2017 7:51 pm, edited 1 time in total.

amc49
Posts: 1183
Joined: Mon Jun 19, 2017 7:24 pm
Car: '11 Nissan Versa
'17 Nissan Altima

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From what I get out of the service manual real quick the code is for the secondary CVT pulley not having enough pressure to possibly slip. It's tied to line pressure and primary pulley pressure and there are solenoids for that that could stick with dirty oil or erratic action just to being old, or even a slight ooze leak at the secondary oil chamber seals. Dirty oil could mess up most of that, of course, if the wear has happened then changing oil may do nothing.

BbNicholas@18
Posts: 3
Joined: Wed Nov 08, 2017 5:01 am
Car: 2012 Nissan Versa SV 1.6 with CVT

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Thanks for the responses.
Still wrestling with the idea of dropping the pan myself and possibly checking the transmission fluid pressure sensor/switch myself with a multimeter. Would need to make sure I knew where it was first. I downloaded the FSM from another site. I am pretty good with electronics but in this case if the sensor or switch is not staring you in the face when you drop the pan, I would not want to take anything else apart.
Still not sure if I should continue driving it and just baby it or take the chance of dropping the pan getting rid of the old fluid and replace.

Troadsy
Posts: 1
Joined: Thu Nov 15, 2018 12:14 pm
Car: 2012 Nissan Versa

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Any chance you ended up figuring this out. I'm at 95k miles and running into same issue. Hoping there is a cheaper remedy other than a new tranny.

jacksoncjoy
Posts: 1
Joined: Wed Mar 27, 2019 4:14 am
Car: Nissan Sentra 2013 model - UAE, Abu Dhabi

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Hi,
Good After noon,

my vehicle nissan sentra 2013 , UAE specification
Two days before dashboard , indicated electrical problem symbol. i checked with workshop. they checked through computer it is showing gear box one sensor problem ( P0846 - Transmission fluid) . kindly advice how can replace this sensor . i checked with auto mobile shop , they don't have this sensor.
by
Jackson
00971556194692


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