Black smoke and high fuel consumption in the 2018 Benz SL-Class: suspected defective lambda sensor

Hey buddy, I know the problem all too well. I had the same thing with my 2015 Benz SL Class. Your symptoms sound really typical of a problem with the lambda sensor. Strongly suspect it's ceramic inside the sensor, which can be dirty or clogged. The last time I was in the garage they diagnosed this with similar symptoms. They had to replace the lambda sensor, not just clean it. The engine control unit receives information on mixture formation via the sensor and if the information is faulty, this causes the engine light to come on and increases fuel consumption. So it's a serious problem, but fortunately it's easy to fix. When you go to the garage, I recommend you tell them about the lambda sensor and ask them to read your fault memory. That way they can find the cause quickly. Don't forget to ask about the correct setting of the idle mixture control and the ignition system, as these are important after the replacement. Hope this helps you. All the best!

(Translated from German)

Hey buddy, thanks for the excellent advice, I'll definitely take it on board. A real nuisance, this whole thing... Do you think the ceramic inside would be broken by then or just dull deposits? And another personal thing: do you remember how expensive the whole thing was when you visited the workshop? After replacing the lambda sensor, did you notice anything else or was there anything else? Looking forward to your answer and thanks again for the help!

(Translated from German)

Hey, no problem, that's what we're here for, to help each other. The last time I visited the workshop, they actually said that the ceramic inside the lambda sensor was quite dirty and clogged. It doesn't seem to be that rare, if you ask me. Regarding the costs: The good piece cost me a good €375. That's not exactly easy on the wallet, but the Benz has been running like a champ ever since. After the exchange, everything was back to normal in my car. They didn't discover anything else and the maintenance was done quickly. Nevertheless, if I were you, I would always keep an eye on the things I have mentioned. So I hope this helps you too and good luck with your Benz!

(Translated from German)

Hey, that reassures me a little. Thanks again for your help. I'm also always of the opinion that you should handle this with mutual support. It's always good to know someone who has already had this kind of experience. 375 is pretty steep, but if it solves the problem, then it's probably worth it. Yes, I'll let the guys at the garage know and hope they can fix it quickly and easily. It would be really great if nothing else is discovered. I'll have it checked first and will keep an eye on the points you mentioned. It's really great that you've shared your experience. Wish you well and keep your fingers crossed!

(Translated from German)