How does the "smell" sensor actually work?

[andrewwynn]

Sensor broken auto will work for other conditions but won't do anything regarding auc. Auto for example will kick on/off recirculating air to defrost. First recirculating to get more heat then outside to get rid of the moisture.

The sound is very different when recirculating air is enabled. Set the fan to medium high speed and hit the recirc then outside air button.

[andrewwynn]

Scanner like foxwell will show both state of fresh air flap and the auc output voltage.

To fake the auc you would need a resistor for the heater and a potentiometer to adjust the fake sensor output

[getty150]

Originally Posted by Henn28

How do you know it has failed? Did it throw a code?

Good question...
From what I've read to understand is that a code is thrown..."auc 20" it's always there and that i should ignore it...and it can't be cleared.
I drive mostly with the no circulation button in the on position.
Just yesterday I found myself at the stop light behind someone with a blacken,smoky exhaust ...
No smelly fumes entered my e83 cockpit .

[Henn28]

Originally Posted by getty150

Good question...
From what I've read to understand is that a code is thrown..."auc 20" it's always there and that i should ignore it...and it can't be cleared.
I drive mostly with the no circulation button in the on position.
Just yesterday I found myself at the stop light behind someone with a blacken,smoky exhaust ...
No smelly fumes entered my e83 cockpit .

Thanks Getty - yep, I've had that code too for a long time. Haven't noticed a difference in the cabin, but I haven't really been paying attention. Couldn't hurt to replace the sensor though the next time I'm making an FCP order.

[getty150]

Originally Posted by Henn28

Thanks Getty - yep, I've had that code too for a long time. Haven't noticed a difference in the cabin, but I haven't really been paying attention. Couldn't hurt to replace the sensor though the next time I'm making an FCP order.

Yeah! I've replaced the sensor (got about 5 of'em)
I've opened it up and put in new filter stuffing.
I've only seen it work once...but I suppose that's because I commonly drive in air flow off mode.
But again you see my account I listed the other day on the road.
Cheers!

[SirHiss]

https://www.youtube.com/watch?v=9ZpSk6d_82U

[getty150]

There you have it!

Sent from my SM-A102U using Tapatalk

[jac]

Thanks for that video link. It led me to this other one, where around minute 16 he shows how to test the sensor :-)

https://youtu.be/JAOxIYI4iG4