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Typical CVT shaking at low RPM, P17F0 after software upgrade

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ValeriyR

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Discussion starter · #1 ·
Hi All,
Murano 2015 has a very common issues for those cars. It may start slightly shaking at rpm around 1000, low speed and slow acceleration. The symptom has been there for the last 4 years since I bought the car and in general was not progressing. There were no any error codes until I upgraded software at a dealership at about 63000. They told me the new software has enchanted diagnostics and may through up an error code after some time of driving if there is a problem. However they also told me they had tested the car and found no any issues with transmission and no any codes. Wether that was before they upgraded the software, because when I connected my scanner just at the dealership parking before leaving the new code immediately appeared. They behaved strange after I told that. Fortunately the upgrade seemed to help, the shaking has not completely gone and became seemingly less. Drove 20000 more miles. However now the error code is persistently sitting there.
If you have read up this point, thank you, and now the question. Is it possible that the software upgrade was not done properly. Particularly the manual describes some “calibration” procedure which is needed when the cvt hardware is replaced. In my case only soft was changed. But I guess might be the new soft required the calibration data the old one didn’t support. Do you know if a dealership can check and perform this calibration even if the cvt was not replaced? Thanks
 
Discussion starter · #5 ·
joesatch said:
and so it begins..
Click to expand...
It is understood that this CVT is very specific and problematic. However for for the last almost 60000 miles and 4 years the problem did not get worse. It may have even improved after ATF change and that reprogramming at a dealer about 20000 miles ago. I test drove a brand new Murano, it felt almost the same. Currently 83000 miles. Pretty sure it will stay by 100000.

Recalibration is a routine procedure on replacing a CVT because the software should be adapted to the specifics of a particular new hardware. One can assume that upgrading software when new calibration parameters are introduced may also need a similar procedure. I doubt the dealer did everything properly especially because they claimed that there are no issues and no error codes, but the error code was there just after the upgrade and was not clearable, so they obviously lied.

Did anyone have a similar issue - an error code popped up just after the software upgrade? And is there any official manual on the upgrading software which may include the missed steps such as a recalibration or other adjustment or training procedure?
 
#6 ·
I had exactly the same problem, i was complaining about rattling on low RPM for a long time. I believe I had 5 visits as there were no codes always had answer its all good.
Till recently at 72K miles, my CVT app showed the P17F1 code.
Drove to a dealer and they cloud see the code. Body valve was the issue, they contacted Nissan and Nissan agreed to pay 80% of the bill. Which was $1.3K for body valve replacement.


Sent from my iPhone using Tapatalk
 
Discussion starter · #7 ·
dand. said:
I had exactly the same problem, i was complaining about rattling on low RPM for a long time. I believe I had 5 visits as there were no codes always had answer its all good.
Till recently at 72K miles, my CVT app showed the P17F1 code.
Click to expand...
As far as i can understand, P17F1 is not exactly the same as P17F0. The latter one is a generic error and might be caused by many mechanical reasons for example a stretched belt rather than the hydro block. However one doesn't excluded the other.

I quite believe my CVT is worn out and the belt might be stretched. But since the symptoms are not so strong for now, it might be worth to check if any software adjustment like another version or the calibration mentioned above is ever possible. Logically thinking the calibration is exactly the procedure to adjust to a particular belt length variations which occur even on new assemblies. The previous version of software worked a bit worse in practice but did not show the error.

Dealerships obviously follow instructions and change by large components and don't want to dig deeper and care only about the price - higher is better for them. Unfortunately I should have came to them earlier before the warranty was expired. After the error poped up after the software upgrade they would have likely replace the CVT. Btw strangely after the upgrade CVTz50 application stopped working properly. And i have no idea what exactly did they install there and how.

Now i am to check if easy ways are possible and then probably will be selling the car later when it is around 100k miles and probably will tell about the error to the buyer.
 
#8 ·
ValeriyR said:
I quite believe my CVT is worn out and the belt might be stretched.
Click to expand...
The "belt" is made of metal and it's "pushed" from the power side pully. The belt, when pushed, is as stiff as a 1/2" dia. steel rod between the two pullies as they're rotating. There's no physical way it can stretch.

There's a video where the guy shows the belt assembly and how it functions in detail on YouTube.

Have a good day.
 
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#10 ·
ValeriyR said:
Then what is the calibration procedure required after the replacement of CVT to a new one? And might it be required after the software upgrade alone on the old CVT?

Click to expand...
"The Service Procedure (starting on page 2) in this bulletin contains the steps to perform TCM Calibration Data “Write” Procedures. These procedures are used when a complete CVT assembly is replaced, a CVT control valve (valve body) is replaced, or a Transmission Control Module (TCM) is replaced."

This is necessary for proper communications with the ECM. Engine operation is closely tied to CVT function, so Nissan has decided that the engine and CVT are a matched set electronically. Similar procedure is needed if the ECM is replaced.

Nothing physical is being adjusted during the procedure, much less the pully/belt assembly.

Have a good day.
 
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Discussion starter · #11 · (Edited)
PaulDay said:
Nothing physical is being adjusted during the procedure, much less the pully/belt assembly.
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That is understood that nothing physically is being adjusted.

But was i wrong to assume that every CVT mechanical assembly has own slightly different mechanical characteristics. The software on the other hand controls if the mechanical parameters are within the expected range. For example it may control output rpm depending on the input and cone pulley position. If the belt length is slightly different or other mechanical parameters differ it may trigger an error. I thought of calibration as of reading and storing the initial mechanical characteristics.

For example on some Lexuses there is a procedure to learn auto windows and power seats by moving them to the final position and holding the button 5 seconds. There are multiple other learning procedures for all other modules, throttle body, steering angle, whatever else. Is not it the same with CVT?

Are you saying that the "calibration" is just a procedure to establish a communication between CVT control block and ECU?

Thanks
 
#12 ·
My understanding is that the engine/CVT goes thru a learning curve when new. Hence changing either one would require a "calibration" of the modules involved.

Every CVT is going to have slight variances in working fluid pressures. Having the ECU aware of these variances helps the engine with fuel economy and performance.

If you glanced at the PDF, it's mostly about erasing existing profiles and having the system learn the new parameters for whatever procedure was completed.

Have a good day.
 
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#13 ·
ValeriyR said:
That is understood that nothing physically is being adjusted.

But was i wrong to assume that every CVT mechanical assembly has own slightly different mechanical characteristics. The software on the other hand controls if the mechanical parameters are within the expected range. For example it may control output rpm depending on the input and cone pulley position. If the belt length is slightly different or other mechanical parameters differ it may trigger an error. I thought of calibration as of reading and storing the initial mechanical characteristics.

For example on some Lexuses there is a procedure to learn auto windows and power seats by moving them to the final position and holding the button 5 seconds. There are multiple other learning procedures for all other modules, throttle body, steering angle, whatever else. Is not it the same with CVT?

Are you saying that the "calibration" is just a procedure to establish a communication between CVT control block and ECU?

Thanks
Click to expand...
The updated program/software that was done to your Murano, Its simply an Enhancement on the logic for diagnostic purposes. It is not a Calibration/Data writing procedure that you keep referring to. The TSB that you are quoting above does not apply to what was done to your vehicle. Explanation of the Enhanced logic and rationale after these Codes: "P17F1 is not exactly the same as P17F0. The latter one is a generic error and might be caused by many mechanical reasons for example a stretched belt rather than the hydro block." These codes were introduced in the new software for a more accurate diagnosis of the "JUDDER PROBLEM" on these transmissions. P17F1 is detected when the slip ratio between the 2 pulleys crosses a determined threshold (Mild judder), this condition requires the inspection of the "Chain" for abnormal wear and or replacement of the Valve body. P17F0 is detected when the slip ratio is so excessive that it might required a sub-assembly replacement. This chain inside the Murano/Maxima/Pathfinder CVT unit does not stretch, They wear abnormally when the the fluid deteriorate after 40k miles without changing it. Hope this helps.
 
Discussion starter · #14 ·
Nissantos said:
P17F1 is detected when the slip ratio between the 2 pulleys crosses a determined threshold (Mild judder), this condition requires the inspection of the "Chain" for abnormal wear and or replacement of the Valve body. P17F0 is detected when the slip ratio is so excessive that it might required a sub-assembly replacement.
Click to expand...
Where did you get it from, can you send the original link please?
 
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