Read out the fault codes this morning:
P 5612: boost pressure electric actuator b2 stiff
P 9510: Air mass (HFM) ahead of throttle valve - implausible
(9510 fault appears twice)

Both are implausible signals.

Also have a P 8121, cooling system performance, but think this may be due to a coolant level low light that came on due to the coolant level not been topped up all the way after the clutch replacement.

Just had a new stage 2.5 Sachs clutch put in (Flywheel was fine so didn't need replacing), and a month ago replaced all the coils and plugs.

Noticed that sometimes under hard throttle in second gear or third, above 4000 rpm, seems like the car's power starts to dissipate. Could this be a pressure leak?

Today in second around 5000 the car had a slight shudder (almost like a misfire - I know what those feel like before I replaced all the coils and plugs), but it only happened once. Could it be related to the clutch It's only got 100km on it?

It's absolutely smooth and perfect in first, and only in the high rev bands when on boost, she feels like she's loosing power.

I should mention I am running a softronic tune (4 months now).

Any input or how to diagnose this (have a durametric basic cable with the software).

Thanks guys - Mike

 

Yes the vtg vanes are stuck in one of the turbos. All symptoms you report suggest that. You ll probably need new turbos but ask your mechanic to lubricate first (as per the factory recall in earlier cars). You lose power in the top end.
Had same thing couple if years ago. Good luck!

 

Thanks GT-TT! Curious are you referring to the same fault codes or behavior or both?
Will definitely look at the turbo actuators.

 

Both. Fault and symptoms indicate that the vtg vanes are stuck in closed mode. Hence the error and loss of top end power. Very typical fault for VTgs.

 

Just wanted to respond that I got the same exact codes literally 1 day after the op's post. Coincidentally I'd just had my car in for Major Service (35k miles 4 years old) about two weeks before so I wasn't sure what to make of the fault.

They said they re-seated some screw and lubed the vanes. It's been over a week now since I had the car back and it is fine.

Pretty sure my car had the original vane lubrication recall done too.

I searched everywhere else on Google for the codes and this was the only thread that came up, which I did find a little odd.

I'm adding turbo vane lubrication to a my list of things to maintain every few years on the car... I can't imagine it would hurt.

 

So I thought I'd end this thread with my update.

It’s been a long slog trying to figure this problem out. Initially the diagnosis was that the turbo’s (both of them) were dead - testing the actuators failed. This is done by pushing them in and if they don't spring back there's generally a major problem with these components.

So after some deliberation, I decided to hop over the boarder to the US to Porsche in Belingham (BTW thumbs up to these guys. Never have I had such good service and customer care - thumbs up to Peter!!!) to see if I can plead on hands and knees to see if they would honor the warranty which had just run out a few months ago. I heard that with Porsche Canada, the chances are much less for them to honor a warranty that has just expired.

As it turned out the actuator rods needed to be replaced. This was done and whalla, the turbo’s are working just fine.

I would highly recommend everyone to put this item on their check list when doing a service. The alternative is being stuck with around a 10k bill to replace the VTG turbos – one I was lucky to avoid.

 

This seems to be my first post, but I have been reading a lot on here. I apologize for bringing this thread up again as I am facing the same problem here.

I am currently having the same EXACT problem. I just had a SACH 2.5 upgrade kit installed together with the slave cylinder replacement on my 997TT. In addition to that, I also had my actuator rods replaced. I have EXACT same symptoms with the threat starter.

I am getting the exact two same codes:

1.) "Boost pressure electric actuator b2 stiff"
2.) "Air mass ahead of throttle valve"

I tried the "Adaption of boost pressure actuator" but it FAILED. I am pretty much stuck now because what it is saying is that there's an actuator fault at b2. I also thought that one or both of my turbo is dead, but after a fresh start my car would pull hard and well in short runs, but when it comes to highway runs, the boost goes limited once again.

I also checked on the intercooler pipes and there were no leaks.

PLEASE HELP.

 

Hi Frankc Z

As mentioned, my problem turned out to be the actuator rods - they were not moving the vanes.

With that I would be real careful if you are out driving the car. My problem snowballed into many more issues - first were the spark plugs (due to the excessive back pressure) the engine management system was doing all sorts of strange things which ate right through a brand new set of plugs in a matter of weeks.

I'd advise you get a second set of eyes to take a look at the actuator rods. Make sure that they are in fact connected (they can come loose) and that they are moving the vanes (vanes aren't stuck.

 

Thank you very much for your reply. I only drove the car in that state for let's say 30-35minutes while trying to find an exit on the freeway to bring the car back to the workshop.

That night, my mechanic came back with the PIWIS and found the 2 faults I stated earlier. We tried adapting and checking the status of the actuators via PIWIS and it never went through. It always ended with with an error and the adaptation fails. The fault of the "stiff b2 actuator remains" unerasable.

With my car in the mechanic's hand, yesterday he called me with an update:
- He tried removing the actuator rods and checked and see if the "actuator adaptation" will go through via PIWIS. It did.
- So he reinstalled the rods again, and tried re-adapting it. It was completed with no error.
- He tested the car and the boost is normal again.

This morning today, I called my mechanic to check the car again. I told him to do a LONG test drive on the freeway using high gears and revs just to make sure the problem doesn't come back again. He said it was okay.

So it seems like it really is the installation of the rods. If this is it, then I am lucky.

It is still kind of weird that, PRIOR TO THE FIX, after I stopped using the car for lets say a few hours and went back to it again, the boost decided to come back to normal, but as soon as I hit the freeway when I can actually let the boost hold for longer than 1 second, the next thing I know I am stuck again (with the fault codes given). Can an improper installation of the rods really cause something like this? If you don't mind can you please share the detailed story on your side?