Turbo problem - Seat Leon Cupra ST300

[karsklane]

Hi guys!

I've read through many of the threads here regarding this issue but I could not get the right answers (at least in my opinion) - if I missed a thread (I've been kind of desperate and tried to scurry through them) and this has been thoroughly discussed before with good solutions then please feel free to copy me the link and I can delete this post . So the story starts with buying a 2020 Seat Leon Cupra ST300 4drive (221 kw) last summer, which now has a mileage of a little over 52 000 km (~32 000 miles).

To my issue: in January while driving the car I noticed that the EPC light had come on, and with it also the Start-Stop failure. Plugged in my cheap OBD and got the codes: "14846" and "15226". Switched the car off, everything was good. Now during this time I've come to the conclusion, as did many others, that this only happens when the engine is cold and it gets over 2k+ RPM and the turbo gets pressure. When the engine oil is above 80+ degrees then the issue does not come and everything works fine.

Now in the summer I noticed that when I got the EPC light I could also feel that the turbo was not working properly (before that time I did not notice any change even when the EPC light was on). The turbo does work, but it starts working at much higher RPM-s. Even tough the issue does not come on very often, I decided to have someone look at it. So when looking at the fault codes with a good diagnostic tool it gave the codes "P256300" and "P00AF00". Since it is a fairly new car and has a lot of electronics, my mechanic spoke with someone from the dealership and told me to go have the diagnostic there as they have a specific tool that will tell you what is wrong. I went there, they reprogrammed the actuator and told me that if this does not work then the next thing is to look at the turbo connection between the regulator (I assume they meant actuator here) and see if it is moving. And if that works then the car needs a new actuator.

Now on to the specific problem on why am I writing here: the reprogramming of the actuator did not clear the issue. Brought it to the dealership and they called me to say that the car needs a new turbo with the regulator. Basically they told me that the connection to the regulator is good and it is moving, they had no complaints about that. But the new turbo with a regulator is needed because you can not buy the regulator separately, which is not what they told me when I first time brought the car there as they stated that the actuator can be replaced. They also stated that even when you can find a place to buy the regulator that there could be issues as it needs to be programmed and since it is electric then it might not clear the issue as it might not work as intended.

I'm turning here in hopes of maybe someone has good recommendations from experience on how to deal with this issue. Is the turbo replacement as a whole with the regulator the only option I got? Or has anyone found a place from where to buy the regulator separately, and has had success programming it so it cleared the issue? Or does someone have other options to recommend so I can deal with this issue? At the moment I'm seriously considering on driving it the way it is (not giving the turbo pressure while oil temp below 80 degrees) as I'm not quite fond of the idea of replacing the whole turbo, especially when it comes to putting in a restored turbo to the car as it is kind of a lottery in my opinion. Another thing I've considered is that if there is a worst case scenario and the car should not be driven with this fault, then I might get an upgraded turbo (which is more pricey, but might help avoid the problem in the future). So to make a long story short, if anyone has any ideas on how to potentially get rid of this problem without buying a new turbo, then please let me know, and feel free to ask additional questions as English is not my first language. Thank you for your help in advance!

 

[adamski310]

I can't help you with the specific problem you posted, but in an older car of mine, that I had remapped the actuator and wastegate went (you could hear it fluttering about and pressure wouldn't build). Similar situation when my own mechanic and the dealer said "you'll need a whole new turbo" so I just upgraded to a mitsubishi one (forget what it was exactly) when the original was a Garrett one. I then tuned it further.

 

[karsklane]

I've pretty much made up my mind that if it comes to replacing the turbo as a whole, then I will think about a turbo upgrade as it seems that turbos are the weak link of the car (based on others experience). Also, the idea of a putting on a restored or even stuck turbo might not clear the issue in the long run. At the moment, as it is not a running issue (I only get it when oil temp is not above 80) and it seems to drive fine after that, has boost etc, then I might just run with it if it does not mean more damage. But as of now I'm hoping for some insight on maybe the actuator itself can be somehow replaced/fixed (without having to spend nearly +2k on a new turbo) or if there are any fixes people have done themselves that clear the issue.

 

[queen]

You can replace the actuator alone, you don't have to change the whole turbo assembly. However, if the actuator isn't faulty it won't fix your issues. What you describe, only happens if temp is below 80, seems weird. A friend of mine had a similar issue with a faulty actuator but in his case everytime when going into boost, regardless of temp, the ECU noticed that the actuator wasn't working properly and disabled the turbo to protect the engine. So it showed 0 boost on the infotainment and the car would drive like a naturally aspirated.
Maybe you should take it somewhere else for a second opinion, preferably a turbo specialist if you have one in your country?

 

[karsklane]

You can replace the actuator alone, you don't have to change the whole turbo assembly. However, if the actuator isn't faulty it won't fix your issues. What you describe, only happens if temp is below 80, seems weird. A friend of mine had a similar issue with a faulty actuator but in his case everytime when going into boost, regardless of temp, the ECU noticed that the actuator wasn't working properly and disabled the turbo to protect the engine. So it showed 0 boost on the infotainment and the car would drive like a naturally aspirated.
Maybe you should take it somewhere else for a second opinion, preferably a turbo specialist if you have one in your country?

Oh really? As far as I've done independent research then Seat does not provide the actuator alone, but maybe VW/Audi does then? And to clarify the below 80 degree one - that is the line I have drawn for myself. But even when at 70 degrees the car does not throw the EPC. I looked over my OBD2 diagnostic screenshot (attaching it below, maybe someone gets more expertise and insight on the matter) and the last time it threw the fault codes the engine oil temp was 33 degrees.

As far as I've compared my situation with others, then for me it really is an anomaly as the EPC light is not a constant thing. It only happens when driven coldly and will not come back if the car is shut down and driven normally until the engine oil gets to a high enough temp. I'm not technically good in the matter, but in my opinion if the regulator is bad, then it should still throw the light (at least periodically) no matter the engine oil temp. There are many theories of something blocking the actuator from fully opening or closing, but they stated that everything moved fine.

I'll try to find a local specialist who might be able to give a second opinion. Does the turbo itself need to be removed to examine the actuator rod movement etc, or can they do that with a diagnostic/test drive aswell? The issue is that the dealership quoted that replacing the turbo means 10.5 hours of work (their words, not mine) as it has to be done from the bottom of the car and I'm not quite fond of doing that now when I don't have the money for a (potential) new turbo .

 

[labombadiesel]

Well, I´ve just arrived on this forum but I have to say something about that problem.
I have exactly same car as you and have had the same issue during the last three years, solving it readjusting the waste gate actuator rod with a diagnostic tool on hand (obdeleven).

Seat won´t solve it anyway because they always will tell you to change the turbo as they told me, but you can solve the problem during a long time (I´ve been doing it during last 3 years) but finally you´l have to change the turbo actuator, or maybe not, nobody knows.

I´ve just talked about it on another post here called "Fault codes" where another member ask for the actuator part number (06K145725T) but I write it again for you:

"The only thing my car had was the fault with the turbo actuator that caused underboost fault, but I´ve been solving that problem readjusting during the last 3 years the turbo actuator rod, unscrewing the nut (below the turbo and is a bit complicated to reach it), spinning the rod manually until the actuator voltage reading on the diagnostic tool obdeleven was between 3,5v and 3,8v and later screewing the nut again and everything was solved until a long time later.

It has worked for 3 years having to readjust the rod every 4 months aproximately (I do 30.000 kms/year), but now with 213.000 kms on the car the actuator rod can´t be sppined any more to adjust it because I think the actuator has reached its final peak, so I´m going to change the actuator and readjust the new one."

I show you more info about adjusting the turbo actuator from two different specialist guys from the USA doing that on a Golf R or a GTI with the same IS38 turbo as ours.

Wastegate First Adaptation of Charge Pressure Actuator | MyGolfMk7

Wastegate First Adaptation of Charge Pressure Actuator with my IS38 turbocharger with VCDS. First time adaptation and P2563 Turbocharger Boost Control Position Sensor Fault.

mygolfmk7.com

I put you here as well the thread I opened a long time ago on an spanish Seat Leon Forum where you can translate everything I wrote if you need it.

Cupra ST300 4drive - Error EPC en cuadro pero funciona bien • Club de Propietarios del Seat Leon

www.clubseatleon.net

I´ll keep on talking about my car´s issue when I can change the actuator.

 

[karsklane]

Hi! Thanks for the input, it's greatly appreciated. I contacted an independent mechanic, who has dealt with this problem before with Seat Leon's. As you have pointed out then the actuator can be separately replaced and that is what I will do when my mechanic returns from his vacation. The original actuator part will be around 200-300 euros + about 4 hours of labor. Beats the hell out of the 1900 euros I was quoted from the dealership for restored turbo and 10.5 hours of labor!

Before ordering the part and doing the work I will have my mechanic rediagnose the issue(so far I've only had over the phone conversations about the actuator and if it is available separately) just to be sure, as I'm not quite trustful of the dealership diagnosis. Hopefully the diagnosis will stay the same and it is the actuators fault and the turbo itself is OK. I will update this thread if the work is done or if something new arises from the problem!

 

[labombadiesel]

Ok, and yes, replacing the actuator is a hard labour because that part is just on the downside of the turbo and to reach it is quite complicated.

Anyway, I'm not completely sure, but I think that it's possible to replace the actuator without taking out the turbo, reaching it from under the car, removing some parts like the heat shield and the turbo's oil return pipe, as the seat guide on the "Faults code" thread shows.

As well, maybe your mechanic should try first of all to recalibrate the actuator rod as they show on the links I posted above, because maybe you can save your money not having to replace the actuator and only readjusting it.

What I can assure you is that the waste gate turbo actuator calibration is known only by few people, of course none of them being from the Seat dealer shop or even some chiptunners, because I tried to all ask to all those people before finding those infos on the internet and nobody has any idea about it.

Well, have luck and I wait for you to tell us how you've solved it.
Meantime if I solve it before you I will write it here...

 

[karsklane]

As well, maybe your mechanic should try first of all to recalibrate the actuator rod as they show on the links I posted above, because maybe you can save your money not having to replace the actuator and only readjusting it.

What I can assure you is that the waste gate turbo actuator calibration is known only by few people, of course none of them being from the Seat dealer shop or even some chiptunners, because I tried to all ask to all those people before finding those infos on the internet and nobody has any idea about it.

As per the dealership information, the first thing they did was readjust it, but it did not clear it. But before going to the shop my mechanic told me that he will try to readjust it just to confirm if the actuator is in fact the problem.

Anyway, I'm not completely sure, but I think that it's possible to replace the actuator without taking out the turbo, reaching it from under the car, removing some parts like the heat shield and the turbo's oil return pipe, as the seat guide on the "Faults code" thread shows.

Yes, changing the actuator does not mean taking the whole turbo down. But the process itself will still take around 4 hours. But hey, better than the 10.5 hours for the whole turbo replacement. Will see soon how it will come out.

 

[labombadiesel]

Ok, so please, if you repair your car before I can repair mine I would appreciate much if you can confirm me that the part number 06K145725T is the correct one for our electronic waste gate turbo actuator, because I´ve been searching and investigating a lot about the correct part number and it´s been a hard work to reach that part number as the good one and even some suppliers telling me that they weren´t sure about it´s suitable for my car.

 

[karsklane]

Ok, so please, if you repair your car before I can repair mine I would appreciate much if you can confirm me that the part number 06K145725T is the correct one for our electronic waste gate turbo actuator, because I´ve been searching and investigating a lot about the correct part number and it´s been a hard work to reach that part number as the good one and even some suppliers telling me that they weren´t sure about it´s suitable for my car.

Unfortunately I haven't heard back from my mechanic yet. Don't know if he took an extended vacation or is just busy. But there is still time til the end of this week as he promised to contact me this week. I'll let you know as soon as I get some info.

 

[labombadiesel]

Unfortunately I haven't heard back from my mechanic yet. Don't know if he took an extended vacation or is just busy. But there is still time til the end of this week as he promised to contact me this week. I'll let you know as soon as I get some info.

Have you got any news from your mechanic about the turbo actuator?

 

[karsklane]

Have you got any news from your mechanic about the turbo actuator?

Nope. He still hasn't contacted me. As it is starting to annoy me and the EPC came on today even when I didn't push hard enough to get turbo pressure, then I'll go down there tomorrow and try to get a time or find someone else who is willing to do the job.