Hey guys, I'm trying to figure out what is up with my smog sensor. When I have it set to auto (yes both auto on the a/c and on the circ) it stays only on Recirc (judging mainly by the two lights Recirc and auto that stay on) I have no problem with fresh air if I select it manually and I've cleaned the smog sensor (twice! ) yet still I've never seen it switch to fresh air after 5000 miles. Sometimes in NYC I'd understand but it NEVER changes even when I'm upstate NY which is hardly smoggy - not sure that's a word. Also I've tried it in varied temperatures and set to varied temps to no avail.
It's not a major issue but for someone who doesn't know exactly how a car works I like when everything does and would love to figure it out.
I've searched pretty extensively on the forum and don't think I've found anyone else with issue - so lets hear some ideas! Thanks, you guys are great and let this thanks go out for all the threads I've read through old and new, that have been awesome!

 

did you try to change the sensitivity of the smog sensor?

 

Just some thoughts - mine has worked properly, switching between the two automatically:

1. Would "cleaning" the smog sensor perhaps damage it in some way?
2. How is the sensitivity set? (I have a manual and service manual, but sometimes it's just easier to ask)
3. Even if it isn't nasty outside, if it is really hot my car will switch to recirc just to keep the interior cool. Once the outside cools down (which it hasn't much lately in the midwest) it will switch as well. I can tell when it switches because the humidity of the outside air is just slightly more than if it were on recirc.

I know none of this really helps you - perhaps it could be a bad sensor? The only way I'd know is to take it to a dealer unfortunately; I've never really worked on the internals of a car with this many cool features

 

Hey, sorry forgot to say that I have changed the sensitivity to the lowest. On ES with nav you just hold the vent button (that switches from Recirc to fresh air) for a few seconds and the sensitivity menu comes up (Lexus would like to remind you this will not work while the car is in motion - for your safety
As far as cleaning damaging the sensor - maybe but all I did to clean it is open the sensor vacuum and wipe down. And as to the auto switching of the vents due to temp and maybe humidity, that works in my car I think, maybe it is a bad sensor but I'm hoping for something more interesting (and cheaper - DIY)

 

Ok how about this, could anyone tell me how a smog sensor, senses?