2012 BMW 335i AUC Sensor

In this video, I will show you how to replace the Air Conditioning Automatic Recirculation Control Sensor (AUC Sensor). If you get code A6CF this sensor is to blame. This sensor will not tell you with any lights or annunciations in the car that it is bad. You will only find out if you scan the codes or if you can tell that when you have the AUC mode enabled, bad smells continue to enter the cabin.
The part is very easy to get to just behind the engine bay under the hood. The part number is stamped on the part. I searched eBay for my part # (9240-190-01) and found several listed for $30-$60.

[@kar4tube]

I just completed a major refurb of my '09 135i earlier this year. Have replaced turbos, suspension, nearly every sensor, hoses, seals, mounts, bushings etc. Finally took her out on a fairly long distance drive today. All in all trouble-free; except upon returning home I scanned for codes and got the A6CF code. Chalking up another sensor replacement! Just ordered a new one from ECS for $73. I wouldn't waste my time or money on a used one. Thanks for the helpful tip here!

[@JRsGarage]

When you save thousands on labor you can afford to pay more for parts!

[@g_dawwg]

thanks for the vid, broFessor! Exceptional video and audio quality, zooming right in on the subject so I can see what you're illustrating! And military phonetic spelling to boot!

[@JRsGarage]

Thanks for the comments. Go AF, beat Army!

[@mannysingh8295]

Yes it will my friend. Just replaced 1 on e90 2011 an fixed my issue wot uv described

[@JRsGarage]

Great.

[@Tom-Fisherman]

Capital M is mega-Ohms. small m is milli-ohms

[@Shroommduke]

It's supposed to be, isn't it! Little m for milli- and big M for Mega-...

[@new2me78]

I bought an auc sensor off eBay for like $30 cause I didn’t see it on fcpeuro and I’m like if it doesn’t work oh well. It finally arrived today after a month maybe (china) the part was a bit different but connection was the same and my code is gone! Just two more codes to fix. I had 2aaf which I still do. I replaced the pressure switch thing but I still have the code sadly

[@JRsGarage]

Glad to hear you got the AUC sensor fixed. Good luck on the other 2 codes.

[@bathanmark]

Hello, may air recirculation in the car sometimes goes to A instead of M where I placed it. Is it because of this? they switched by itself from M to A. thank you

[@JRsGarage]

No, I do not think that is how it is supposed to work. Mine does not do that.

[@bathanmark]

@@JRsGarage yes true.do you have a idea why it does that? I see in OBD gives error E71470 E71472 say something abouy IKHA

[@JRsGarage]

Sounds like something wrong with the switch or electronics board. Maybe try disconnect the AUC sensor and see if it happens again just to rule that out.

[@bathanmark]

@@JRsGarage thanks for the input. I will give that a go. Thanks.

[@erikjohansson8916]

Does this code get the engine light to come on?

[@JRsGarage]

I believe it does.

[@jannplanken]

@@JRsGarage No it doesn't, its a silent code. You'll only find it by scanning your car for fault codes. Its not a critical sensor, only difference is it wont automatically switch to re-circulating air in a polluted environment if the sensor is faulty.

[@JRsGarage]

Thanks for the information.

[@RodriguezSteve]

Would this cause my fans to stay on ?

[@JRsGarage]

No, it is my understanding that it only closes or opens the recirculation.

[@RodriguezSteve]

@@JRsGarage yeah my fans are blowing like crazy, the the temperature light comes on ( reduces my rmp to lower 900-1k... No smoke but then the car turns off

[@JRsGarage]

Are the fans running as soon as you turn on the car? Or does it heat up and then the fans come on? What's happening to the engine temperature gauge during this time?

[@RodriguezSteve]

@@JRsGarage yeah exactly like you said it. I just replaced the valve cover but I'm not sure if I was low on coolant so the temperature light came on ( not the coolant) after that the car would start to slowly lose power and it turns off

[@RodriguezSteve]

@@JRsGarage I don't have a temperature gage on the 2011 series, it just shows my temperature warning go from yellow to red then the car starts to not let me get acceleration