BMW i3 Hybrid Issues: Check Engine Light & Rough Running

Hey there! I have some experience working on cars, and I actually dealt with something very similar on my 2018 BMW i8 Hybrid last year. I feel your pain! When my check engine light came on and the engine started running rough, I initially thought it was something major. After taking it to my workshop, it turned out to be a faulty cable connection to one of the sensors. The repair was pretty straightforward, they replaced the damaged wiring and connections, which cost me about 95 Euro. Mind sharing what error codes you're getting? Also, how long has your engine been running rough? These details would help me determine if it's the same issue I had with mine. The i3 and i8 share quite a few electrical components, so I wouldn't be surprised if it's a similar problem. My also has a BMW X5, and these sensor connection issues seem to pop up in the BMW family from time to time.

Thanks for the response! Just had my service done last week, and I'm currently at 153134 KM on the odometer. The engine started running rough about three days ago, and I'm getting error code P0480. The rough running is most noticeable when I first start the car in the morning. It's definitely concerning since it's been consistently getting worse. The water sensor theory came from my mechanic but I'm starting to think it might be electrical like your case. Did you notice any particular patterns with your rough running before you got it fixed?

Hey again! Glad to hear back from you. Interesting that you're getting the P0480 code, that's actually different from what I experienced with my i8, which makes me think we might be looking at different issues here. With my car, the rough running was pretty unusual, not specifically tied to cold starts like yours. Given that your issues are worse in the morning, and considering the P0480 code (which is related to the cooling fan control circuit), I'm starting to think my initial suggestion about the wiring might not be the whole story. Since you mentioned the mileage, my i8 had about 145000 KM when I had my issues, so pretty similar to yours. But looking back at your symptoms, especially the morning rough running, I'd actually lean more toward your mechanic 's water sensor theory now. These BMWs can be pretty sensitive to cooling system issues. Just thinking, have you noticed any changes in your coolant level? In hindsight, I probably should've asked this earlier. Also, does your temperature gauge read normal? This could help confirm whether we're dealing with a cooling system issue rather than the electrical problem I initially thought it was. Sorry if my first response sent you in the wrong direction. These hybrid systems can be tricky, and sometimes similar symptoms can have completely different causes.

Thanks so much for the follow-up! You actually helped me narrow things down quite a bit. I checked the coolant level like you suggested, and it's definitely lower than it should be. The temperature gauge has been reading normal, but I did notice some slight fluctuations I hadn't paid attention to before. I really appreciate you sharing your experience, even though it turned out to be different from my situation. You made a good point about hybrid systems having similar symptoms but different causes. I've scheduled an appointment with my mechanic for tomorrow, and I'll have them specifically check the cooling system and water sensor. The morning rough running combined with the P0480 code and low coolant level seems too connected to ignore. I'll keep you posted on what they find. Thanks again for taking the time to help me work through this!