# 2018 Sentra erratic shift on highway hills



## LukeBurrier (3 mo ago)

The 2018 Sentra with 46k miles is erratically shifting while going up hills at highway speeds 65+ Mph. Once I hit the bottom of the hill going up, it losses it’s spot and starts to bounce around from 2500 rpm to 3300 rpm and doesn’t stop up I get over the hill or left off the gas completely. The vehicle has strong vibrations during this time and doesn’t speed up but slowly loses speed. There is no codes store and the dealership, I’ve sent it twice to them, says they can not duplicate the issue. I would attach the video but it’s not allowed so I’ll attach two images to show the range it tries to shift in.


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## rogoman (Dec 16, 2004)

Most likely there's a problem with the CVT/TCM. First thing to do is perform a TCM code readout. The code readout is essential. P17F0 and P17F1 never turn on the MIL on any Nissan model. P17F0 is the CVT "death code", it means severe belt slippage was detected. There are "judder detection" codes in almost everything 2013 and up that give a quick estimation of the CVT's condition and usually determine what fix is applied. P17F1 generally means a new Valve Body as long as a belt inspection doesn't reveal damage. Minor slippage causing a P17F1 can often be resolved with timely fluid changes; you can still possibly save your CVT by replacing the fluid ASAP *but don't do a fluid flush*, just a drain/fill only. A flush can possibly introduce fine particles into the system further complicating the issue. 

To be able to read CVT codes, download a copy of the CVTz50 app for an android smartphone and get a VeePeak VP11 adaptor for your OBD-II port (the VP11 is the cheapest ELM327 that works correctly with CVTz50, not all of them do). With that, you can read any CVT codes yourself, read the CVT temperature in realtime, and also check the CVT-A/CVT-B count for any history of overheating. If something bad did happen, at least you'll get an inkling of what it was from the past evidence by seeing that the counts are greater then zero.

Judder will be most pronounced on a moderate to steep incline with light acceleration. Let off the gas at mid-hill, let the car coast momentarily down to 20~30 mph, then apply enough pedal to roll back up to speed. It should transition smoothly. If you feel any shuddering or surging, or the tach starts jumping around without pedal input, that's judder.


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## LukeBurrier (3 mo ago)

Weird shifting I hope that worked but yeah it does it on an long hills and and just horrible on hills overall and no code will share.


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## LukeBurrier (3 mo ago)

rogoman said:


> Most likely there's a problem with the CVT/TCM. First thing to do is perform a TCM code readout. The code readout is essential. P17F0 and P17F1 never turn on the MIL on any Nissan model. P17F0 is the CVT "death code", it means severe belt slippage was detected. There are "judder detection" codes in almost everything 2013 and up that give a quick estimation of the CVT's condition and usually determine what fix is applied. P17F1 generally means a new Valve Body as long as a belt inspection doesn't reveal damage. Minor slippage causing a P17F1 can often be resolved with timely fluid changes; you can still possibly save your CVT by replacing the fluid ASAP *but don't do a fluid flush*, just a drain/fill only. A flush can possibly introduce fine particles into the system further complicating the issue.
> 
> To be able to read CVT codes, download a copy of the CVTz50 app for an android smartphone and get a VeePeak VP11 adaptor for your OBD-II port (the VP11 is the cheapest ELM327 that works correctly with CVTz50, not all of them do). With that, you can read any CVT codes yourself, read the CVT temperature in realtime, and also check the CVT-A/CVT-B count for any history of overheating. If something bad did happen, at least you'll get an inkling of what it was from the past evidence by seeing that the counts are greater then zero.
> 
> Judder will be most pronounced on a moderate to steep incline with light acceleration. Let off the gas at mid-hill, let the car coast momentarily down to 20~30 mph, then apply enough pedal to roll back up to speed. It should transition smoothly. If you feel any shuddering or surging, or the tach starts jumping around without pedal input, that's judder.


I posted the video above


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## Shade Tree Squatting (3 mo ago)

LukeBurrier said:


> The 2018 Sentra with 46k miles is erratically shifting while going up hills at highway speeds 65+ Mph. Once I hit the bottom of the hill going up, it losses it’s spot and starts to bounce around from 2500 rpm to 3300 rpm and doesn’t stop up I get over the hill or left off the gas completely. The vehicle has strong vibrations during this time and doesn’t speed up but slowly loses speed. There is no codes store and the dealership, I’ve sent it twice to them, says they can not duplicate the issue. I would attach the video but it’s not allowed so I’ll attach two images to show the range it tries to shift in.
> View attachment 9767
> 
> View attachment 9768


Replace the MAF sensor


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## Shade Tree Squatting (3 mo ago)

Shade Tree Squatting said:


> Replace the MAF sensor


You can clean it about every 3 or 4 months. Nissan put a transmission in my car and that didn't fix it! Free new transmission is always good but.... I spent a month on this after the transmission was replaced and finally figured it out, it pulled no codes???


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## Shade Tree Squatting (3 mo ago)

Shade Tree Squatting said:


> You can clean it about every 3 or 4 months. Nissan put a transmission in my car and that didn't fix it! Free new transmission is always good but.... I spent a month on this after the transmission was replaced and finally figured it out, it pulled no codes???


A CVT transmission will slip all the time if it's going out, not just on hills. If you floor it and it consistently does the same thing under a heavy load every time then the CVT is bad.


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## 1.8TTony (5 mo ago)

Obviously this is the classic crappy Nissan automatic transmission situation..... Stop trying to think that you can fix this with fluid change or filter change or transmission change because these transmissions are garbage....., Your remedy is to buy a completely new transmission for $5,000 to make your $3,000 car operate properly again


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