Insufficient Boost/Vacuum Problems

[RuthHimmic]

Hello, I own a 2013 E250 CDI 2.1 Diesel. 76,000 miles.
I have had the vehicle for a year, however in the last 4-5 months, the Engine Check Light has on, and there has been a deficiency in power.

I get code P0299 (Low boost) using a diagnostic checker, and I may erase the code. However, a few miles down the road, it reappears.
I have verified with the Smoke Tester that all vacuum lines are free of leaks. Intercooler and both hoses are in satisfactory condition.

Nonetheless, the EGR actuator fails to engage upon ignition or acceleration. The actuator operates freely with the vacuum hand pump.
In the absence of a vacuum in the system, the brake servo would undoubtedly exhibit symptoms; yet, the brakes remain precise and forceful.

I am seeking suggestions. Can anybody assist?

[MercedesMan98]

The P0299 code is often caused by turbocharger problems or a boost leak. I acquired it when my turbo malfunctioned.

[85KillallRU]

These are often associated with the lower intercooler pipe, I believe. Have you verified it again? I previously had one that only leaked under pressure, however it sealed well for the smoke test.

[RuthHimmic]

Thank you for the information. I removed both the red and black components, meticulously inspected for fractures or damage, and examined the internal O-rings.
Both seemed attractive. The reinstallation was completed, followed by the execution of the Smoke Test, which included connecting to the Red Hose before installation onto the Turbo, while inspecting the intercooler and the subsequent black hose.

[veroguittar]

Examine the vacuum transducers. They often fail due to not maintaining a vacuum.

[RuthHimmic]

Thank you for the information. Where are they located?