BMW X1 O2 Sensor Woes, High Fuel Usage Warning Signs

Hey there! I had nearly identical issues with my 2018 BMW X3 last winter. The symptoms match exactly what you're describing, check engine light and increased fuel consumption. Initially thought it was the O2 sensor too. Took it to my mechanic and it turned out the connections to the O2 sensor were corroded and loose. The wiring harness had some wear and tear, causing intermittent connection issues. It wasn't actually the sensor itself that needed replacement. The fix involved cleaning the connections and securing the wiring properly. While it wasn't a major repair, leaving it unfixed could've led to more serious problems with the fuel mixture and catalytic converter down the line. My suggestion? Get it checked soon. The symptoms are pretty clear indicators of either a sensor issue or connection problem. Just make sure they properly diagnose whether it's the sensor itself or just the connections before replacing parts. Hope this helps with your decision.

Thanks for sharing your experience! That's really helpful to know about the wiring harness issue. Would you mind telling me roughly how much you ended up paying for the repair? Also curious if you've had any similar problems pop up since getting it fixed? Thanks!

Hey again! Just wanted to follow up, since I had it fixed, absolutely zero issues! The mechanic found it was indeed just like I suspected, an aged oxygen sensor with some connection problems. They sorted out the cable/plug connection and it cost me 95€, which I thought was pretty reasonable considering how much better the car runs now. The fuel consumption went right back to normal after the repair, and the check engine light hasn't shown its face since. I know we were both worried about potential bigger issues, but sometimes it really is just these simple fixes that do the trick. My car's been running like a charm for months now. Just goes to show that getting these things checked out promptly usually saves headaches (and money) down the road. If you end up going for the repair, I bet you'll notice the difference right away like I did. Let me know how it goes if you get it sorted!

Thanks for the update! I actually took your advice and got it checked out yesterday. Funny enough, my issue was a bit different, turned out to be a completely clogged air filter along with a minor vacuum leak. The whole thing set me back about 150 bucks, but wow, what a difference! The mechanic I found was super transparent, showed me the gunked-up filter, and explained everything. Really glad I didn't put it off any longer. The car's running so much smoother now, and the check engine light finally went dark. Fuel consumption has already started improving. It's such a relief to have it sorted. Thanks again for encouraging me to get it checked out promptly. Sometimes it's the simple things that make the biggest difference. Really appreciate everyone's help with this!