2012 x35d. What are these items?
 

This is my fourth BMW.

Car has 98k miles on it and I’m doing the usual exploration.


Sensor dangling near the cabin air filters. https://uploads.tapatalk-cdn.com/202...52e860499c.jpg


Unit at left front corner of engine makes buzzing sound even with the engine off.


https://uploads.tapatalk-cdn.com/202...00cfdc39c6.jpg


Hardware found lying loose in the cabin air filter compartment.

https://uploads.tapatalk-cdn.com/202...41e2986bf6.jpg


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The first foto, is the air polution sensor, if you select the correct button, the airvent valve will close automatic when the air is dirty. ( thats what understand from the Manuel)

Thank you. Found it on Realoem.


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https://xoutpost.com/data:image/jpeg...RMhERAREQP/9k=


Pic 2: throttle body

https://3a663eb0fef48c6d2d60-a88f8eb...47254_x800.jpg

pic 3:


https://www.ecstuning.com/b-genuine-...g/11612246947/

Realoem says there’s 7 of these on the intake manifold. How did it get in the cabin filter compartment? More to explore. Thanks for the pointer.


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Thank you. Any ideas about the buzzing sounds?


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My guess is a prior owner (or mechanic) was digging around in the intake and set this up on the cowling, it dropped into the fresh air intake? Just a guess. Id wonder what they were doing digging around.


Not sure about the buzzing. I think diesels have a throttle shut off that will operate after the motor turns off. Could be something going on with that? mine makes some noises when off (or shortly after shut off, then quiet), but has since mile 1- so Ive not paid much attention to it.

Here's more technical info that explains what the AUC sensor is detecting...and when it does...it closes the fresh air flaps of the IHKA system:

Sensor for automatic air recirculation control

• The AUC sensor is fitted on the microfilter compartment. The AUC sensor detects the following pollutant emissions from spark-ignition and diesel engines:
  • Hydrocarbons (CH )
  • carbon monoxide (CO)
  • Nitrogen oxides (nitrogen monoxide NO, nitrogen dioxide NO2)
  
  
  
  The junction box supplies the AUC sensor with voltage. The junction box electronics evaluate the data of the AUC sensor. The junction box electronics unit transmits relevant data to the IHKA control panel (via the K‐CAN).

Thank you.


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