BMW 1 Series Cabin Odors Linked to Failed AUC Sensor

Hey there! I had a similar issue with my 2014 BMW 3 Series diesel. The AUC sensor problem is actually more common than you'd think. Last month, my car was giving me the same symptoms, strong odors in the cabin and blower issues. Took it to the garage and turned out the wiring harness connecting to the AUC sensor was damaged, causing intermittent failures. The connector had some corrosion too. They had to replace the wiring and clean the connection points. The sensor itself was fine, just the cable connection was faulty. It wasn't a major repair but definitely needed fixing since the AUC sensor controls your cabin air quality. Without it working properly, you're getting all those exhaust fumes and outside pollutants in your car. Not good for your health, really. If you're worried about choosing a garage, look for one that specializes in BMW electronics. That's what made the difference in my case. They spotted the issue quickly because they'd seen it before. Hope this helps with your decision.

Thanks for sharing your experience! That's really helpful to know about the wiring harness being the culprit. Would you mind telling me roughly how much you ended up paying for the repair? Also, has everything been working fine since then, or have you noticed any other issues pop up? Trying to get an idea of what I might be looking at cost-wise and whether it's a lasting fix.

Hey again! Happy to tell you that since getting it fixed, everything's been working perfectly, no more nasty smells or blower problems. The AUC sensor's doing its job just like it should. I paid 95€ for the repair, which included fixing the cable and cleaning up the corroded connector. Much cheaper than I expected, honestly! It's been about three months now, and I haven't had a single issue pop up. The cabin air is fresh again, even when I'm stuck in heavy traffic. The blower's back to normal too. Definitely worth every penny, especially considering how much time we spend in our cars. The mechanic mentioned these connections can get dodgy over time, but once they're properly fixed, they usually stay sorted. Just make sure whoever works on it knows their way around BMW electronics, that's really the key to getting it done right the first time. Let me know how you get on with yours!

Thanks so much for all the info! Your suggestion really paid off. I took your advice and found a good BMW specialist. Turns out my issue was pretty similar to yours, corroded wiring was the main problem. They fixed it last week, and I've got to say, what a difference! No more awful smells in traffic, and the blower's working perfectly now. The repair cost me a bit more than yours, around 120 bucks, but it included a full diagnostic check which spotted a couple of other minor issues they fixed while they were at it. The mechanic was super thorough and explained everything clearly, such a relief after my last experience! Really appreciate you taking the time to help me out with this. It's such a weight off my mind having it sorted properly. Could've wasted so much more time and money if I hadn't known what to look for. You were spot on about finding someone who knows BMWs, definitely made all the difference!