C Klasse check engine light and stalling issue

Sounds familiar. I had a similar issue with my Mercedes C Klasse. The check engine light would pop on and the engine would sometimes stall when I stopped at lights. Does it happen more when the engine is cold? It could be a dirty throttle body or a faulty IAC valve, like a clogged artery in your car's breathing system. Have you checked those?

Thanks for the quick reply. You mentioned the IAC valve. Where exactly is that located and how difficult is it to clean?

The IAC valve is usually attached to the throttle body. Finding it can be tricky. Some models have it easily accessible, others bury it. Cleaning it isn't rocket science, but you need to be careful with the electronic components. Given your description and the mileage it is likely related to a heavily contaminated intake system. Honestly, if you're not super comfortable working on engines, I would suggest taking it to a reputable workshop. The error memory definitely needs reading. My eventual repair cost was around 425€.

Thanks for the input. I took your advice and had it checked out. Turns out the IAC valve was indeed the culprit, just like you thought. They cleaned the throttle body and replaced the valve. Car idles perfectly now and the check engine light is off.