Cabin air recirculation wont stay on

[Raimo5]

Hi,

I have an issue where manual cabin air recirculation mode disengages itself after a minute or two of running. The air circulation button light goes out while A/C button light stays on. It happens both in auto and manual modes, regardless whether automatic air recirculation mode is active or not.

Wonder if others are experiencing same behavior as well or is it just me. Seems pretty useless feature if it's like that by design.

[Atavus]

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.

[M_Bimmer]

Originally Posted by Raimo5

Hi,

I have an issue where manual cabin air recirculation mode disengages itself after a minute or two of running. The air circulation button light goes out while A/C button light stays on. It happens both in auto and manual modes, regardless whether automatic air recirculation mode is active or not.

Wonder if others are experiencing same behavior as well or is it just me. Seems pretty useless feature if it's like that by design.

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.

[Raimo5]

Originally Posted by Atavus

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.

Originally Posted by M_Bimmer

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.

[M_Bimmer]

Attached SI B64 01 19

[Raimo5]

Originally Posted by M_Bimmer

Attached SI B64 01 19

Oh, that seems to be just the cure for my issue! Many thanks for pointing out that procedure.