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

Hey, I had similar problems with my 2013 Mercedes ML diesel some time ago. In my case, it was the lambda sensors. The symptoms were pretty much the same: lots of black smoke, the check engine light came on, significant loss of power and a strong exhaust smell. At the garage, the mechanic diagnosed the defective lambda sensor and replaced it. This was actually a more serious problem, as the lambda sensors play an important role in exhaust gas aftertreatment and engine performance. After they were changed, my car ran perfectly again. I would therefore recommend that you have the lambda sensors checked. When it comes to workshop recommendations, of course it depends on where you live. But in general, it's worth looking at a few reviews and, if necessary, visiting a mechanic who specializes in exhaust aftertreatment. Good luck! Best regards

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Hey, thanks for your detailed answer! That really sounds like a similar problem to mine. Do you remember how much you paid for the repair? And has anything else come up with your ML since then? Best regards

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Hey, sure, I can tell you. After I went to the mechanic, the "exhaust aftertreatment malfunction" was completely fixed. The repair cost me €375, as the fault was in one of the lambda sensors. Since then, my ML has run smoothly and no further problems have arisen. I hope this helps you! Best regards

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Hey, thanks for the info! That at least gives me a good idea of what I'm in for. So, I actually made an appointment at a garage that specializes in exhaust aftertreatment. The mechanic there was super friendly and looked at my car straight away. As it turned out, my lambda sensor was also defective. The repair was a bit more expensive than yours, I paid around €420, but it solved all the problems. No more black smoke, the loss of power is gone and the exhaust smell has also disappeared. I can hardly believe I've been driving around with these problems for so long. Many thanks for the tip, it really helped me! Best regards

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Sorry to hear about the issues you are facing. To me it sounds like a DPF or EGR problem. I recommend seeking a reputable specialist or mechanic. All the best!

It seems like ThomBraun has already resolved the issue with his car by replacing the defective lambda sensor. The symptoms he described earlier have disappeared after the repair. Therefore, your suggestion might not be necessary at this point.