BMW i8 Hybrid CEL: Charge Air Sensor Woes and Power Loss

Hi there! I've got some experience with hybrid cars and had a similar issue with my 2015 BMW i3. I'm not a pro mechanic, but I've learned quite a bit from maintaining my hybrids over the years. Had almost identical symptoms, CEL, power loss, and that distinctive whistling noise. Turned out to be a loose connection in the temp sensor wiring harness. My local workshop found the problem pretty quickly, and they fixed it by replacing some worn-out cables and securing the connections properly. Cost me about 95 Euro total, and it's been running perfectly since then. Before I share more specific details about the fix, could you share: Have you noticed any changes in fuel efficiency? Does the noise get worse when the battery is low? Which diagnostic code are you getting exactly? Also, given that the i8 has a different cooling system layout than my i3, knowing these details would help me give you more relevant advice.

Thanks for sharing your experience! I've got exactly 16202 KM on mine, and just had my last service about 2 months ago. Actually, I have noticed a slight drop in fuel efficiency lately, especially when running on hybrid mode. The noise definitely gets louder when I push it hard, and the diagnostic code I'm getting is P0096. The whistling seems more pronounced after the car's been running for a while, especially during spirited driving. The workshop I usually go to isn't very familiar with the i8's hybrid system, so I've been a bit hesitant about letting them dig too deep into it. It's good to know your fix was relatively straightforward and affordable. The symptoms do sound pretty similar to what I'm experiencing. Did you notice any battery performance issues after you got it fixed?

Hey again! Thanks for those extra details about your i8. Those symptoms do sound really familiar, my i3 was doing the same thing, especially that whistling getting worse during hard acceleration. After getting mine fixed, the battery performance actually improved a bit. I think the sensor issue was making the system run inefficiently. My fuel economy went back to normal too, which was a relief because I was getting worried something more serious was wrong. Looking at your mileage and the P0096 code, I'm even more convinced it's similar to what I dealt with. The fact that it's more noticeable after the car's warmed up is another typical sign. My mechanic mentioned that heat can make these connection issues more apparent. Quick tip from my experience, I'd strongly recommend finding a workshop that specializes in BMW hybrids. I learned this the hard way after a regular mechanic made things worse by trying to fix it. The hybrid system is pretty complex, and while the fix might be simple, you need someone who knows what they're looking at. Have you checked if there are any BMW certified hybrid specialists in your area? The extra cost of going to a specialist might be worth avoiding potential complications. My repair was straightforward once I found the right mechanic to do it.

Thanks so much for all the detailed info! I really appreciate you sharing your experience, especially about how the battery performance improved after the fix. I'll definitely take your advice about finding a BMW hybrid specialist, honestly, that's probably the smartest move rather than risking my regular mechanic making things worse. I've been doing some research and found a certified BMW hybrid workshop that's got good reviews. Going to give them a call tomorrow and set up an appointment. Feeling much more confident now about getting this sorted, especially since your symptoms were so similar to mine. Just hoping it'll be a simple wiring issue like yours was! I'll make sure to have them check those connections you mentioned, particularly since the noise gets worse with heat. Really don't want to risk any damage to the hybrid system. Thanks again for the help, it's been super useful having someone who's been through something similar!