nele_schmid72

Mercedes S Klasse diesel engine rough cold start

My 2013 Mercedes S Klasse with a diesel engine is acting up. It only has 35050 km. When cold, the engine runs super rough during the start. The computer's throwing an error, and my fuel consumption has gone through the roof. I've heard it might be the PTC heater causing issues with temperature control. Is this some kind of electrical fault? Could it also mess with the blower motor or the whole HVAC system? Has anyone else had this problem before?

4 comment(s)

Sounds familiar. I have an S Klasse too, and I had similar issues with the cold starts and increased fuel consumption. An electrical fault in the PTC heater was the culprit. Have you checked the error codes to confirm?

Yeah, I checked the error codes. It does point towards the PTC heater. But I am not sure if this is something I can fix myself. Is it a big job? Did you end up doing it yourself, or did you take it to a mechanic?

I didn't risk messing around with the electricals myself; it can get pretty complicated. I took it to a workshop. They confirmed it was the PTC heater. If you aren't confident with electrical work, I wouldn't advise attempting it yourself. Best to get it checked out professionally.

Thanks for the advice. I took it to a trusted mechanic, and you were spot on. It was indeed the PTC heater, and the whole HVAC system was acting up. Cost me around 350€ to get it sorted, but now it's running like a dream again. Really appreciate the help.

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