Hi Experts,

I changed/replaced transmission oil on my 2014 QX60 Infiniti @68K, then change it again after 800 miles. I bought this @65K and transmission oil was never charged. I was trying to get 70-80% of new oil with multiple changes.

Not sure if it's related to the transmission replace service but now I'm getting P171F Code. Which is transmission related i.e CVT Judder.

Wondering if someone had seen similar issue before and what remedy you took and what your experience had been. It can be related to valve body replacement but wanted to check with others for their experience.

Also what's the dealer cost for diagnosis this?

Thanks

Are you sure the P17F1 wasn't already there when you bought it? There's really no reason for a properly-done fluid service to cause it.

P17F1 is a "minor slip" code and lots of people are driving around completely unaware that they have one. The judder codes don't light the MIL but also don't erase, reflashing the TCM is the only way to clear them. P17F0 usually means it's too late and there's already belt damage, but P17F1 is often simply a harbinger of poor fluid quality. If your tranny is asymptomatic, the fluid changes may well have saved its life and you can simply put up with the hidden code.

If you want it checked out, it requires dropping the Valve Body and inspecting the belt with a borescope. It's a PITA operation and the dealer will likely charge you a pretty penny for it. However, there's a very explicit how-to bulletin for DIYing the inspection if you want to jack the front end and rent a borescope from the parts store. That will also save you replacing all that fresh fluid again, you can catch and reuse it. The dealer won't do that:
https://static.nhtsa.gov/odi/tsbs/2016/ ... 2-2280.pdf

Hi VStar650CL,

Thanks for prompt response. Fluid was replaced with the scan tool and proper instructions were followed. I'm feeling that it may be the triggering event.

Re: code being present their, i didn't run the diagnostics when buying, but when changing transmission oil i ran scan not sure if it was full system scan using but no code highlight then, so not sure if i ran the right test . After 2 of the fluid changes i bought a different scan tool, ran a full system scan that highlighted the code.

I called the dealership and they are asking 220 for diagnostics and suggest based on that. I'm also thinking that if I can reflash TCM instead of getting it checked?

I talk to a mechanic who also suggested to keep driving if there is no obvious sign of slipping which i don't but its a common problem as well with these engines.

Can i pass inspection with this code?

Thanks

It's very -- well, no, extraordinarily -- unlikely that a proper fluid change incited any kind of judder code. It's much more likely that you bought the car that way and scanner #1 simply couldn't read it. Many cheap ones don't read anything but the engine.

I dunno about inspection, but if you're in Cali I expect they could flunk you for a dirty windshield. So it won't surprise me if that represents a problem.

Hi VStar650CL,

Here is what i'm thinking let me know if its crazy. Based on the document you shared if chain is not Ok then the end result is new tranny which is worst case. But if its just the VB that needs replacement then many people have been driving with that code and not even knowing it exist, either i can continue to drive like this or change the VB sometime.

Just not sure that if having this code will lead into some other failures?

Thanks

No, that sounds perfectly rational. The code probably won't mean future problems provided 1) the belt passes inspection, and 2) you keep the fluid fresh. That all depends somewhat on whether the poor fluid caused anything in the VB to wear prematurely, so that's where the "probably" comes in. However, even if that turns out to be true, the worst case is a new VB and not a new tranny. I'm sure you noticed in the bulletin that your CVT has a chain belt and not the "puzzle piece" belt used in the 4 cylinder CVT's. Primarily for that reason, the V6 trannies are much stouter than the I4's. With a P17F1 at 68K, my gut tells me that not only was the previous owner a zero-maintainer, but he/she was also a leadfoot who killed the fluid prematurely with shear and heat. If that theory is right, your belt should be fine and the code was just a canary in the fluid pipe. Check the belt and make sure, but if it's okay, I'd say drive it and enjoy.

One more thing. Depending how honest your dealership is, there may be a lazy tendency for them to say "f#ck it" and tell you the tranny is shot. Print the bulletin and walk in with a copy in your hand, and ask for a digital copy of the borescope video. That will preclude any monkey business and assure that you get a fair assessment.

Hi VStar650CL,

You are really helping and i really appreciate.

I was thinking of not going to dealership at all for diagnosis. Reason is if chain is already bad then damage is done and then it just waiting for the worst. Unless chain is somewhat bad and there is still chance to save tranny. But if that's not the case means chain is still good then its really down to VB and car continue to drive fine.

The only thing i don't know is, what are the symptoms to know if VB really gets bad and not working at all and it really needs to be replace. Or how long i can continue to drive with existing VB before i really have to replace it.?

I do plan to do a DIY diagnosis sometime in April just need to rent a borescope and follow the instruction it the document your shared.

Bad VB's will always start throwing codes besides judder, usually P0776 or P0841. Get a copy of CVTz50 and a suitable ELM327 dongle (I like the VeePeak VP11, it's the cheapest one that works right). That will let you keep total tabs on the tranny's performance, including temperature.

Hi VStar650CL,

Does VeePeak VP11 shows live CVT transmission fluid temp? I'll be needing that for transmission fluid change. And can it read judder code.

Because one cheap one i've didn't read any code at all. Where there was few other like back good, air bag etc which i was able to clear.

After changing the VB i still need to get it re-programmed with the dealer for code to disappear right?

Thanks

malik712 wrote: ↑

Tue Feb 27, 2024 9:23 am

Does VeePeak VP11 shows live CVT transmission fluid temp? I'll be needing that for transmission fluid change. And can it read judder code.

The VP11 is just a dongle which lets your phone talk to the car, the CVTz50 app is what actually does the talking. And yes, there's pretty much nothing about your tranny which CVTz50 can't tell you, in realtime.

malik712 wrote: ↑

Tue Feb 27, 2024 9:23 am

After changing the VB i still need to get it re-programmed with the dealer for code to disappear right?

Correct. The judder codes are unclearable by any other means.

Hi VStar650CL,

Sorry for not being clear but that's what i meant that if VP11 can provide the info for an app to monitor ATF temp as live stream. I bought another ODB scanner which only shows static temp and you've re-run the diagnosis to get latest temp which wasn't great.

Looking at the replacement cost

Valve Body is : 1200+
With all other replacement parts its around 1500.

Any suggestions on finding it cheaper or if aftermarket is even recommended but would like to avoid for transmission.

Thanks

Yes, CVTz50 can livestream temperature, along with almost everything else you can think of.

I don't know if they even make remans, but I'm pretty sure Nissan doesn't (although they do reman whole trannies). If it isn't OE, I wouldn't trust it.

BUT (big but), like I said right at the top, there are tens of thousands of people driving around with P17F1's who are completely unaware that they have one. It's really a warning and that's all. So if the belt checks out and you have no other symptoms or codes, my advice is either leave it alone and call it good, or have the TCM reprogrammed and then leave it alone and call it good.

Hi VStar650CL,

Do you know what is the difference between 3170E-29X9C (~600) & 31705-29X0C/31705-3WX0B(replacement part) (~1200) seems like the same but about double the price. Its listed in latest part# section >> https://static.nhtsa.gov/odi/tsbs/2019/ ... 2-0001.pdf

So you are recommend getting belt checked?

If i assume belt/chain is bad without checking then my option is limited anyway as the damage is already done so i just wait until tranny hit the end of life. Bright side i assume chain is good and P17F1 is just a warning then i can do nothing and continue to drive until i started to see some other code Or just get TCM re-programmed that and call it good.

Thanks

malik712 wrote: ↑

Wed Feb 28, 2024 12:29 pm

If i assume belt/chain is bad without checking then my option is limited anyway as the damage is already done so i just wait until tranny hit the end of life. Bright side i assume chain is good and P17F1 is just a warning then i can do nothing and continue to drive until i started to see some other code Or just get TCM re-programmed that and call it good.

That's exactly why -- well -- I'm sure you know what "assume" means. Check the belt and you can then make an intelligent assessment of what you need, not fret about the cost of parts you probably don't need.

Hi VStar650CL,

Do I need PID to add to the app before i can see the trans temp. I got the VP11 and installed "Car Scanner ELM ODB2" and it does not show the temp. Add need to add the PID for it to be visible and wondering if you know what the PID is.

Thanks

No, the temperature should be coming up in "CVT Data Monitor." I never had to change anything on mine, although for the wife's '13 and my antique S6 phone, I did need to check the v2.15 Workaround, Samsung Extensions, and Bluetooth Compatible Buffer in the "Settings" pulldown.

The "CVT Data Monitor" is the function in the CVTz50 app? Wondering i need to get that app instead of "Car Scanner ELM ODB2" .

I dunno anything about that app, I thought you were talking about the ELM adaptor. CVTz50 is the only app I know about which will read CVT parameters. General-purpose scanner apps like Torque Pro and NDS-III won't do it.