Mercedes Citan problems with the engine, engine indicator light keeps coming on

Hey, I had similar problems with my 2013 Mercedes Citan. The symptoms sounded almost exactly the same - black smoke, engine light, less power, and a strong exhaust smell. In my case, the problem was a defective lambda sensor. The workshop found that the lambda sensor was not working properly and was messing up the exhaust values. This led to the black clouds of smoke and the drop in performance. After the defective lambda sensor was replaced, the engine ran smoothly again and the exhaust gas values were back in the green range. It wasn't a super serious fault, but it should still be rectified promptly to avoid consequential damage. Good luck!

(Translated from German)

Hey, thanks for your quick reply! Good to know that it was the lambda sensor in your case. Do you remember roughly how much the repair cost? And have you had any other problems since then or is the Citan now running perfectly again? Best regards

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Hey, yeah, right! The repair cost me almost exactly €375 because one of the lambda sensors was broken. Since the visit to the mechanic, the exhaust aftertreatment malfunction has finally been rectified. The Citan is now running perfectly again and I haven't had any further problems so far. I hope this helps you! Best regards

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Hey, thanks for the info! That sounds reassuring to know that the repair wasn't extremely expensive. I'll be taking my Citan to the garage in the next few days to have the lambda sensor checked as well. Hopefully it's nothing major. Let's see how it turns out. Thanks again for your advice! Best regards

(Translated from German)

Hi there, it sounds like your Citan might have a clogged DPF or an issue with the EGR valve. I've had similar problems with my car in the past, and a professional cleaning or replacement fixed the issue. I'd recommend visiting a professional mechanic for a thorough diagnosis. Good luck!