Mercedes GLE boost pressure issue resolved

That sounds super familiar! The same thing happened to my old Volvo V70. Engine light, felt like I was towing a boat anchor. It turned out to be a vacuum leak. Have you checked the hoses connected to the intake manifold? They can get brittle and crack. Have you heard any weird hissing noises? Is there any chance your diverter valve or bypass valve is stuck open? It messes with the boost. How recent was the scan and do you know any specific codes?

I appreciate the information regarding potential vacuum leaks and the condition of the hoses connected to the intake manifold. I will inspect those thoroughly. I have not specifically paid attention to hissing noises, but will listen for them. I am unfamiliar with the diverter valve or bypass valve, so I will research this further. The diagnostic scan was performed approximately one week ago; I do not recall the specific error codes.

Those valve things can be sneaky. Worth a look online to see where they are on your engine. A leak is a right pain. Honestly, with those symptoms and the mileage, and without the specific code I'd suggest taking it to a shop. Let them smoke test it, they'll find the leak quick and easy. Good luck!

An inspection revealed a defect in a vacuum switching valve, which was replaced. The total cost was 140€. The engine now operates as expected.