I bought a 2015 C400 Mercedes in December 2024 from a Pennsylvania dealer. Car had just over 43,000 miles
Hopefully this thread will be useful for others.

 

First sign of trouble was the vaccum pump check valve on 2/28/2025.
Symptoms: Burbing noise from transducer, vacuum leak in the intake system
Effect: It can cause ECU to reduce torque load or soften throttle.
The diaphragm was soaked in oil.
Mileage: 46,000 approximately.

Resolution: I ended up buying the Volvo part 31430964 and it includes the screw. $79.00 + tax = $ 88.09 out the door.
The spout is a little thicker so I had to use force for it to engage. So far so good!

I have not heard the transducer act up but then again it can only be heard with the hood up. I should of checked for oil inside
line but did not.

 

Common: https://mbworld.org/forums/w212-amg/...ve-repair.html

Can also install an external one that might act as a permanent fix in the linked thread.

 

It makes sense in theory but needs to be tested. $3 is super low! Almost scared to try it.

 

Someone installed that actually, does work.

 

Starting reading from post #283 then on (Read the quoted post as well that forum member replied to): https://mbworld.org/forums/mercedes-...ml#post9099104

 

Oof wrong link, this link takes you to post #283 directly: https://mbworld.org/forums/mercedes-...ml#post9100449