BMW 5 Hybrid Charge Sensor Causing Power Loss & Whistling

I had a similar issue with my 2014 BMW ActiveHybrid 3 last year. The symptoms were nearly identical, power loss, weird whistling, and that annoying hissing noise during acceleration. Turned out the wiring harness connecting to the charge air temp sensor was corroded and had a loose connection. My mechanic found that moisture had gotten into the connector, causing intermittent sensor readings. The fix required replacing the wiring harness and the sensor itself since corrosion had damaged the connector pins. Not a super serious repair, but definitely something that needed immediate attention to prevent potential engine performance issues. The repair itself took about 2 hours. Worth noting that this wasn't just a simple sensor replacement, they had to test the entire circuit to ensure there weren't any other damaged connections. Since then, no more issues with the charging system. Hope this helps with your decision. These hybrid systems can be tricky, but it's usually just sensor or connection related rather than major mechanical problems.

Thanks for sharing your experience! That's really helpful and sounds exactly like what I'm dealing with. Quick question, do you remember roughly how much you ended up paying for the repair? Also, has everything been running smoothly since they fixed it? Just want to get an idea of what I might be looking at cost-wise and if it's a lasting solution.

Hey there! Happy to give you an update. I just got my car back from the mechanic last week actually, and I can confirm it was definitely worth getting it fixed. They found exactly what I suspected, a faulty cable connection to the charge air temp sensor. Total bill came to 95 € which honestly wasn't as bad as I was expecting. The best part? All those annoying symptoms are completely gone now. No more weird whistling or hissing noises during acceleration, and the engine power is back to normal. The check engine light has stayed off too, which is always a good sign. I know I mentioned in my first post that I had this issue last year, but having just been through it again, I can tell you these sensor problems can pop up from time to time in these hybrids. The important thing is getting it sorted quickly to avoid any bigger issues down the line. Trust me, once you get it fixed, you'll notice the difference right away. My car's running like a dream now, smooth acceleration, no weird noises, just how it should be. Definitely worth every penny of that repair bill.

Thanks for the detailed update! You've honestly made me feel a lot better about getting this fixed. Just got back from a repair shop actually, found a new mechanic who specializes in hybrids and had great reviews. The issue turned out to be pretty similar to yours. Had a corroded connection that was causing the sensor problems. Total repair came to about 120, bit more than yours but still reasonable considering I was worried it might be something major. They replaced both the sensor and wiring to be on the safe side. Took it for a test drive after the repair and wow, what a difference! No more weird noises, power's back to normal, and the engine's running super smooth. Check engine light's finally off too. Really glad I didn't put this off any longer. Thanks again for sharing your experience, it really helped me make the decision to get it fixed right away instead of waiting around and potentially making things worse. Fingers crossed it stays running this well!