helmut_zimmermann1

S Klasse engine issue

Has anyone encountered this issue on a 2018 Mercedes S Klasse with a gasoline engine? At 186358 km, the check engine light appeared, and now the engine stalls at idle with reduced power. I suspect a fuel volume regulator or high pressure pump problem, with engine misfire and rough idling. I'm assuming this involves some car sensors. Has anyone experienced something similar before I start car maintenance?

4 comment(s)

That sounds familiar. I had similar symptoms on my S Klasse: check engine light, rough idling, and power loss. If it's the high pressure fuel pump, it's not a cheap repair. Have you checked for error codes? It could be a faulty sensor triggering the fuel regulator issue.

I retrieved the codes, and they indicate a fuel volume regulator problem. You mentioned a similar issue; was it definitely the high pressure pump in your case? Did you also have engine misfire codes?

The codes pointed to the regulator, but the high pressure pump was the actual cause. It made the regulator generate errors. Yes, I remember the engine misfire too. Given those codes and symptoms, I'd suggest having a workshop confirm it. It's best to be sure before replacing parts.

Thanks, I appreciate the information. It sounds like the high pressure pump is the problem. I received a quote for around 1510€, which isn't great, but at least I know what to expect.

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