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      03-31-2024, 10:17 AM   #4
Raimo5
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Drives: BMW 740d xDrive (G11)
Join Date: Feb 2023
Location: Estonia

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Quote:
Originally Posted by Atavus View Post
I’d expect it to revert after a few minutes as it’s reducing the air quality in the car.

If it’s set in iDrive it should work automatically as needed. This does depend on it detecting pollution.
That's pretty much what is says on many BMW owner manuals now, but G11/12 manual has it a bit differently. I guess they have updated IHKA functionality via update at some point, or manual just sucks.

Technically yes, it is reducing air quality, but puke all over the cabin would do that as well. Have you ever smelled a combo of Green Suite No. 2 and sea kelp? I mean ... fuckin hell, you better have some puke bags ready in the car. Some scents really dont mix. And problem with automatic air recirculation is that it detects irritants and carcinogens, mainly carbon dioxide and nitrogen oxides. It does nothing for harmless smell that we humans might perceive obnoxious and want to avoid.

This short operating window of this mode makes it almost useless as I find that I usually need recirculation for longer than that. A/C is perfectly capable of dehumidifying the air so condensation should not be an issue. And I don't mind being slightly oxygen deprived ... if I have to.




Quote:
Originally Posted by M_Bimmer View Post
Raimo5, when you put recirculation into "M" (aka manual) do you get a change in cabin blower noise volume? You should as the fresh air stratification flap should close, and the internal cabin stratification flap should open, allowing the cabin blower noise to increase (nothing blocking the noise) from the passenger's footwell.

If you don't hear a change in blower motor noise, then there might be an issue with the cabin stratification flap.

Have you run ISTA and run the stratification test plan?

In cabin air "M" recirculation mode, none of my BMW's ever "exit" this mode and to be fair, even in "A" mode, the light always stays on, independent of the stratification flap's position, so if your LED goes out after a minute or so in "M" or "A" or both, I suspect you have a flap or IHKA issue.

Truth be told, I never quite noticed the switchover in G11. That might also be down to me running HVAC in rather low speeds and only in zones that are occupied. Regardless of that, there are no fault codes present and I can physically smell and feel the switchover, so all should be good in that department. It might just be the time limited function described above or condensation sensor might be overriding it. What I experience happens around freezing temperatures with high relative air humidity. Its characteristic function might be different in cooling only mode and might not ever reveal itself to people living in warm climates. Can't remember how it behaved last summer so I'll remember to test when it gets warmer here.

Also, for sake of ambiguity, G11/12 only has single mode recirculating air button on IHKA panel. Automatic Air Recirculation can be toggled from climate settings in CID. I have that option ticked.

Last edited by Raimo5; 03-31-2024 at 02:08 PM..
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