2006 320d innenraum filter - need expert oppinion!

Hi,

I'd like to ask for some BMW expert oppinion.

I have a problem with my AUC Automatic recirculated-air control/Recirculated-air mode. During this time of year I am getting all kind of bad smells from the outside, and it's very annoying. But my my air circulation is set to cabin only - flap for intake of outside air is permanently shut off all the time during driving(right-hand LED on button displayed in E90 manual and in explanation below)! It seems like that bad smells get sucked in cabin from some hidden hole or ventilation hose crack. Sorry, I'm not an expert in explaining this, but I almost instantly receive all specific bad smells, when I pass for example chemical factory, or old Renault Traffic X(, or some wood fire,... Nevertheless, I have replaced the filter two weeks ago, it's not active carbon, but no difference before and after the replacement.

I would like to confirm two statements which I have received at our BMW forum, but I'm just not sure of them, because they doesn't make much sense to me.

1st statement: "all that matters here is 'aktivkohle innenraum filter'!" I'm not sure of that, since: a) the mentioned flap is positioned after the filter and in case that it should be closed permanently, it wouldn't matter at all; and b) my R. Laguna has ordinary filter (no active carbon), with undoubtedly less sophisticated ventilation system, but the incoming bad smells are on minimum when the mentioned flap for intake of outside air is closed.

2nd statement: "when air recirculation is set to manual - closed position (button's right LED ON) - the flap is not permanently shut off, it actually automatically opens every 4 to 12 minutes, because it has to take in some outside air"! That also doesn't make much sense to me, because: a) this function's purpose is supposedly manual, as opposite to automatic (A - button's left LED ON); and b) it's also stated in manual that when this function is ON the supply of outside air is permanently shut off. If this 'manual' mode automatically opens the flap, to what purpose does the opposite (A) function serve?!?

I am going to change the filter back to "active-carbon", that's the least for me to do. But I'd really like someone to please explain these functions in details to me and give me some constructive suggestion if there IS a problem besides active-carbon filter.

extract from E90 manual:
>LEDs off: outside air flows in
continuously.

> Left-hand LED on, AUC mode: a sensor
detects pollutants in the outside air. If necessary,
the system blocks the supply of outside
air and recirculates the inside air. As
soon as the concentration of pollutants in
the outside air has decreased sufficiently,
the system automatically switches back to
outside air supply.

> Right-hand LED on, recirculated-air mode:
the supply of outside air is permanently
shut off. The system then recirculates the
air currently within the vehicle.

thanks in advance and best regards,

Alex

Zitat von oguz

Sorry but i dont understand, what your Problem is. If you have AUC Automatic u need the charcoal filter (Aktivekohle Filter). If it smells bad than change your Filter and do an air conditioner disinfection.

If your turn on the Automatic, the system regular the fans and the Temperatur and turn off, when the Temperatur is reached!

The supply of outside air SHOULD be permanently shut off in recirculated-air mode. But on our forums some experts are trying to convince me that it doesn't mean permanently shut off, because the flap still automatically opens from time to time. It should't if it's supposed to be permanently shut off. The flap should automatically open and close in AUC mode, not in recirculated-air mode.

This is important in trying to solve my actual problem, that during this extremely "bad smell" weather/season I have a recirculated-air mode turned on all the time, and I still get all the bad smells in anyway. We checked the flap and it works fine, it closes nicely and 'dichtung' is OK too. So I would need to find out where to start looking for the spot where the bad smell get in... And it's not the conditioner disinfection problem, because I get specific bad smells from outside (chemical factory, smog,...).