You have a vacuum leak somewhere. A 12 year old car is going to have them, as the rubber dries out and starts to crack. The fact that it turns off when you press the EC button on your climate control indicates that it is probably one or more of your climate vacuum actuators leaking. Depending on their location, these may or may not be accessible without removing the dash. Had to do this job on my 190e, but that was a totally different car, so I can't offer you any advice on the procedure with your 202.

Do a search. I believe this has been discussed a number of times before and you might just find a procedure or guide for doing it on the 202.

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2000 c280 Sport (looks like an upgrade, feels like a downgrade)
1991 190e 2.3 (sold)