Black exhaust fumes and increased fuel consumption in Toyota Corolla petrol 2015: cause and solutions

Hi, I actually had similar symptoms with my Toyota Auris, model year 2012. These constant black exhaust fumes, engine judder and also increased fuel consumption. Don't get distracted by the lambda sensor heater theory. In my case, the control unit was defective, and yes, it was a serious problem. The mechatronics engineer read out the fault memory and analyzed the fault pattern and replaced and reprogrammed the control unit accordingly. The whole engine control unit story made my car very driveable again. The black exhaust fumes have disappeared, no more jerking and fuel consumption has also normalized. So I would suggest you take your car to a garage and check the ECU as it seems to be very similar.

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Hey, thanks for the tip! I hadn't thought about the control unit. It's good to know that your Auris is running normally again after the change. Can I ask how much it ended up costing? I want to prepare for this and would like an idea. Has anything else come up since then? Many thanks for your help!

(Translated from German)

Hey, you're welcome! Well, it wasn't cheap fun. It cost me around €1000 to repair the engine control unit. But since then everything has been running like clockwork and that annoying lambda sensor heater is no longer a problem. It was definitely worth it. So, get ready to pay the money if you have the same symptoms. Let me know how it turns out!

(Translated from German)

Wow, that sounds pretty expensive. But if it helps, it would certainly be worth it. It's definitely better than being annoyed by constant black exhaust fumes, a juddering engine and increased fuel consumption. I now realize that I can't avoid a visit to the garage. I'm off to the mechanic tomorrow and hope it goes as smoothly as it did for you. Thanks again for your advice and for sharing your experience! I'll keep you up to date. See you then!

(Translated from German)