Hi, I have a C350e (S205) from Dec 2015 and since a month I have problems with the airmatic suspension. I heard that this is a common problem for this car. I wrote a timeline with problems I had so far. And sorry for my English, I'm not a native speaker

Timeline:

15 Feb 2022:
Yellow warning with car icon only (no gears or up arrow) but the car was driving fine (I don't know the drive mode anymore). When I parked the car days before I used the raise button because of a high curb, I don't know if this has something to do with it but I don't use that button normally.

16 Feb 2022:
After reading the forum I suspected an airmatic fault and tried the button for raising the car to check if it still worked.
From that point the airmatic suspension was stuck at the highest level, it did nothing when selecting different drive modes.
And the yellow warning was still visible sometimes when driving the car.

21 Feb 2022:
Visited the Mercedes dealer. When I drove away from home the car was still stuck at highest level and when I arrived at the Mercedes dealer, the car was back in the normal position.
Very strange because I also drove the days before and nothing changed and every time I had a very bouncing ride
They used Xentry for diagnosis and this fault code was visible:

N51/3 - Airmatic
C157300: The correction time while emptying is too long.

Their advice was to replace the compressor and valve block if this will happen again. But for now they cleared fault code because the airmatic system was working.
After this the car was driving normal for more than a month but I drove in Comfort and Eco mode only (high fuel prices in NL :p).

22 Mar 2022:
I selected Individual Mode as drive mode and chose for a sport(+) suspension configuration. Everything was fine and I was able to drive in this mode for a couple of days.

25 Mar 2022:
This morning I started the car and after a couple hundred meters I got the red warning:

Car too low. Stop the car.

The car was was really low like the pictures I saw on the internet, wheels where in the wheel arches like a low rider.
I immediately stopped the car and put it in P. After selecting drive mode Comfort the car was raising again and was back at a normal level.
I thought I keep it in Comfort and hopefully it would be fine for this ride. But on the highway I got the same warning again, I was able to stop the car safely and I did the same and the car raised.
Then I drove straight to the Mercedes dealer, it was not very far away and nothing happened. Of course they didn't have time and I did make an appointment for next Monday.
I took the risk to drive home because that wasn't far away either and all was fine. The car is parked in front of my home and everything still looks normal.

Now I really want to know what is wrong with the airmatic suspension. I don't think it is a leak because the car holds its level when parked. And also the compressor is doing fine when it's activated, I can hear it and it isn't running too long when activated (5 - 10 sec). I think it isn't controlled the right way. Maybe it is a sensor fault, compressor relay, pressure relief valve or the valve block?
And I don't understand that they advised to replace both the compressor and the valve block? Are both broken or are they always replaced at the same time? I'm very curious what they are going to tell me next Monday when they do a new diagnosis.

Is there someone that recognizes this behavior/fault and point me in the right direction?

Thank you in advance.​​

UPDATE
26 Mar 2022:
Car is still parked at the correct level and I just tested all different drive modes while parked, went from Comfort -> Individual Mode (Sport+ suspension) -> Raise button -> Sport+ -> Raise button -> sport+. The car changed levels according to mode it was in.
So the airmatic system is not completely malfunctioning.

 

My advice is to keep the car in its normal suspension level. Assume you don't have airmatic. Thank God my car don't have this feature. Your other option is to head to your dealer and pay big $$$.
I was wondering if this airmatic system can be permaently deactivated ie as if it doesn't exist.

 

The compressor is replaced. It wasn't able to produce 13-16 bar pressure during the test.
Airmatic system is working fine now, but it was a quite expensive fix (1349 euro).