The positive control deviation in boost pressure control is very high. The engine is an M642 with 123900 km.

[BentleyOwner]

Hello I previously mentioned my 2011 CLS 350 (218) experiencing an unusual limp state without dashboard lights, and the diagnostic code indicated a defective Y77/1 Boost pressure positioner. My independent mechanic recommended replacing the turbo, but following advice from here, I decided to replace the turbo actuator instead. I have just finished replacing it this morning with a reconditioned one from Turbo Vanes. Additionally, I replaced the worn seal on the main turbo inlet and the one on the breather to the left side of the batwing assembly. Everything proceeded well, but after a 25-mile test drive and considerable acceleration to ensure the turbo was functioning properly, the vehicle slipped into limp mode again without any dashboard lights indicating an issue. An error number on my inexpensive OBD scanner indicates: 'The positive control deviation during boost pressure control is too high'. After restarting the vehicle or clearing the code, it functioned well, however the issue recurred after another test drive. Any thoughts on the possible identification of this? Thank you

[BentleyOwner]

Removed the batwing and applied oil on the new seal, which had some oil residue from previously.

[MercedesFan2022]

It is usual to have a little amount of oil coming from the PCV system hose.

[BentleyOwner]

Thank you. I replaced the O-ring on the output pipe of the turbo and applied a turbo cleaner into the intake to improve performance. Performed a mild test drive after using the turbo cleaner as suggested by Wynn's. Need to have a more thorough drive and accelerate aggressively to see whether the trouble number reappears.

[BentleyOwner]

Still seeing the problem number and the vehicle is still operating in a limited capacity. Turbovanes recommended checking for carbon blockages in the vanes, but I don't believe that is the issue. I used a can of cleanser as previously advised. They also recommended a smoke test to detect air leaks. Any recommendations or advice on this? Thank you

[Olivia_Johnson92]

Inspect the turbocharger and intercooler since these are likely the primary causes of this error number.

[MercedesMan98]

Any news, friend?

[godisgreat]

I am experiencing a problem where the STAR indicates low and high boost pressures, causing the vehicle to go into limp mode. Please provide us with an update on whether the issue has been handled and the method used to resolve it. Thank you.