BMW M2 O2 Sensor Problems? Troubleshooting Guide Inside

Hey there! I can relate to your issue. I have some experience working on BMWs and faced something very similar with my 2014 BMW M4 last year. The symptoms were exactly the same, check engine light, higher fuel consumption, and error codes popping up. Initially, I also thought it was the O2 sensor, but when I took it to my trusted workshop, they found it was actually a loose cable connection to the sensor. Total repair cost was 95 Euro, mostly labor for diagnosing and fixing the connection. Before I can share more specific advice, could you share: What error codes are you getting? Did you notice any unusual sounds? How long has the check engine light been on? By the way, if you're comfortable with basic car maintenance, you might want to check the connections yourself first before heading to a shop. Just make sure the engine is cool before you start poking around. Let me know these details and I can try to help you further!

Thanks for the detailed response! My last service was about 2,500 KM ago, and with my current mileage at 125,877 KM, I'm getting error codes P0171 and P0174, which suggest a lean fuel mixture. No weird sounds so far, but the check engine light has been on for about a week now. I've been hesitant to check the connections myself since these newer BMW models can be a bit tricky to work with. I'm thinking I should probably take it to a specialist who knows their way around M2s. Do you think it could still be just a connection issue in my case?

Yeah, I totally get your concern! Those error codes you're getting with your M2 actually sound quite familiar. When I had my M4 issue, I initially got similar lean mixture codes, but in my case, it turned out to be that loose connection I mentioned earlier. But here's the thing, with your codes P0171 and P0174 showing up together, and considering your mileage is pretty similar to what mine was (I was at around 130,000 KM), it might actually be more than just a connection issue this time. In my experience working with these engines, when both banks show lean conditions, it could indeed point to an aging O2 sensor. After my initial connection fix, I actually had to replace my O2 sensor about 6 months later when similar symptoms came back. The sensor replacement made a huge difference, my fuel economy went back to normal and the engine felt much smoother. The repair cost me about 300 Euro including parts and labor. You're absolutely right about being cautious with newer BMWs, they're pretty complex machines. I'd definitely recommend getting it checked by a specialist. These symptoms aren't something you want to ignore for too long, as running lean can potentially cause other issues down the line. Let me know what the specialist says, I'm really curious to know if it turns out to be similar to what I experienced!

Thanks so much for sharing your experience! It's really helpful to hear how your similar situation played out. Based on what you're saying, I'm definitely going to book an appointment with a specialist tomorrow. You're right about not wanting to ignore these symptoms, I'd rather deal with it now than risk more expensive repairs later. I've got a trusted BMW specialist in mind who I've used before, and I'll make sure to mention both the connection possibility and the O2 sensor scenario. The cost you mentioned for the sensor replacement seems reasonable, so at least I know what to expect if it comes to that. I'll update you once I get it checked out, really appreciate all your input and time!