BMW 5 Series Hybrid: O2 Sensor Woes & Fuel Issues

Hey there! I have some experience working on hybrids. I actually had a similar issue with my 2018 BMW 3 Series Hybrid last year. The symptoms you're describing sound really familiar. My car was showing the same signs, check engine light, weird readings, and drinking more fuel than usual. Took it to my regular workshop, where they found it was just a loose cable connection to one of the sensors. Total fix was 95 Euro, mostly labor costs for diagnosing and securing the connection properly. Could you share which error codes you're getting? That would help narrow things down. Also, have you noticed any other changes in how the car drives? My mechanic mentioned these symptoms can sometimes point to different issues in hybrid systems. Hope this helps! Let me know if you need more details.

Thanks for sharing your experience! In my case, I'm getting the P0172 code, and yes, the car definitely feels less responsive when switching between electric and combustion modes. Had my last service about 3 months ago at 63876 KM, and everything was fine then. The issue started just last week. I'm thinking of taking it to a workshop soon, but wanted to check if anyone else had dealt with something similar first. Good to know yours was just a loose connection, gives me hope it might not be anything too major!

Oh hey again! Thanks for sharing those details about the P0172 code. That's actually really interesting because it's different from what I had with my BMW 3 Series Hybrid. That code usually points to a rich fuel mixture issue, which makes sense with your fuel consumption problem. You know what? After dealing with my loose connection issue, I actually had a similar P0172 situation about six months later. In my case, it turned out to be a combination of a dirty MAF (Mass Air Flow) sensor and a slightly degraded O2 sensor. Once both were cleaned and the O2 sensor replaced, the switching between electric and combustion modes went back to being smooth as butter. I paid around 280 for the whole job, including parts and labor. Definitely worth it though, the fuel economy improvement pretty much paid for the repair within a few months. Plus, the car runs so much better now. Given your mileage and symptoms, I'd definitely suggest getting it checked soon. These hybrid systems can be a bit finicky when the sensors aren't working properly. Learned that the hard way with mine! Let me know how it goes when you get it looked at. Always curious to hear how these things turn out!

Thanks so much for the detailed follow-up! Really appreciate you sharing both your repair experiences. That's super helpful about the MAF and O2 sensor combo, makes total sense given my symptoms. Honestly, feeling much better about taking it to the workshop now, especially knowing it might not break the bank too badly. Your repair cost sounds pretty reasonable, and if I can make it back through better fuel economy, even better! I've actually booked it in for next week at my regular workshop. They're pretty good with hybrids, so hopefully they can sort it out quickly. I'll definitely avoid driving it too much until then, don't want to risk making anything worse. I'll let you know what they find when I get it checked out. Thanks again for all the help and sharing your experience, really helped me understand what I might be dealing with!