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Audi Q7 V12 fault codes

1
Hi friends,
I have rebuilt the transmission and it works perfectly, but I have some problems with the turbo (it has 2 turbos), and it shows the glow and the yellow motor lamp.
The turbo doesn't work and I need some help/troubleshoot with these faults:

P154F (005455) Boost pressure regulation
P00AF (000175) Actuator module for turbocharger stuck

It's a Q7 V12 4L.


Many thanks
Thanks given by:
2
It sound like one of the turbos has a seized variable vane ring. This is moved by an electric actuator mounted to the turbos. This changes the angle of the vanes that direct the exhaust gas onto the turbine to give greater spin at lower exhaust pressures and less spin at high pressure/high rpm. This is done to improve turbo boost at low rpm and prevent overboost at high rpm. Both of your fault codes could be caused by this fault. If this turns out to be the fault then a new or reconditioned turbo or turbos is the best remedy. It is just possible that the actuator itself could be faulty but this is far less likely than a carbon clogged and/or distorted vane mechanism.
Please don't forget the Rate (Heart icon at top center of post) & Thanks buttons below. Help is free when you push them.   Handshake
Thanks given by: Taoufik , KriyenKPp , Bogdan Beb
3
Thanks for your answer!
So you think that the fault is the vane mechanism and not the actuator?
The actuator moves the VNT, but the movement is like random , i don t know if that makes sense.
Thanks again for taking time to answer me! Wink
Thanks given by: diagnostix
4
If you remove the actuator carefully you can then move the lever back and forward with your fingers. It should move very easily without any stiff or sticky feeling.
Please don't forget the Rate (Heart icon at top center of post) & Thanks buttons below. Help is free when you push them.   Handshake
Thanks given by: Bogdan Beb , Taoufik
5
Ok, I am going to start with removing the actuator to see if the vane opens or not.
Doea the actuator need an adaptation on something like that?
Many thanks
Thanks given by:
6
Yes if replacing it. No if you refit it without changing anything. If the lever moves freely there is no harm in carrying out the procedure if it is in VCDS. You should research this first however as some VAG vehicles require a special tool for this.
Please don't forget the Rate (Heart icon at top center of post) & Thanks buttons below. Help is free when you push them.   Handshake
Thanks given by: Taoufik
7
I had to remove one side of the actuator to remove the bolts of the torque converter.
Maybe the actuator losed the basic settings.
How I can reset the actuator basic settings?
Thanks given by:

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