ALIGN

I don't know if it's just me but does anyone noticed when you follow an old car (that god know how he passed the smog test), when in recycle air mode it will switch to fresh air therefore all the smell of gas coming from the car in front of you will fill the cabin.

I think this should be the other way around isn't? If you are in fresh air mode and smog sensor detects the presence of smog, it should switch to recycle mode than letting you inhale all the NOx and CO.

Any thoughts?

jda2000

I believe it only works in Auto mode, when the sensor kicks in and goes to recycle mode.

Arty101

In Auto mode, the sensitivity is suppose to be user adjustable although I don't see much difference when I've tried.

SLH

I think the sensor is sensing the inside air, and the car is trying to push the fumes _out_ by introducing more outside "fresh" air. It doesn't seem to realize that the outside air is the source of the problem.

That might make sense if you regularly carry a car load of smokers. For most people in the US, it seems backwards. Mine is a "no-smoking" car, so there is never any source of pollution or smoke inside the cabin. The fumes are almost always from a truck in front of me on the road.

Arty101

That does sound dumb and backwards.

ALIGN

I am in auto mode. It works fine and it stays in recycle mode until you have a smoggy car in front of you then it switches to fresh air mode.

Lodidian

My 2014 ES sucks in foul outside odors when in auto mode.
Even more annoying the ac. Emits a stale moldy odor for a minute or two when I first start it. Dealer says need to turn the system to recycle for a few minutes before turning the car off but that doesn't help.
It's a drive to the dealer and frankly I don't spend the time if I don't have to.
And another thing---the engine noise and vibration in the cabin is very obvious at stop lights is way more than with my ES 330. Dealer says this is normal but no time to argue so hope for some feedback from the group
Thanks

lesz

It is exactly the opposite. The reason why you are getting the stale air is because the Lexus designers, in their (misguided) wisdom, decided to have the climate control system default to recirculate when the outside temperature is around 75 or above. What you need to do is to get into the habit of manually switching the system from recirculate to fresh air. Unfortunately, there is no way to permanently set the system to fresh air. I'm sure that the reason why they decided to have the system default to recirculate is because, by doing so, they are able to get a very small improvement in fuel economy, but my preference is not to have the stale air. When I got the ES two years ago, I, too, noticed the stale air smell. Once I got into the habit of switching to the fresh air mode, it disappeared completely.

jollick

I do not have your odor issue, but, try this as the drain tube could be clogged with a spider nest or other item. On a hot humid day run the car with the AC on but do not move the car. After a few minutes you should see a small puddle of water under the front half of the car. If not, I would suspect a clogged drain tube that can easily be remedied. I had this happen to a car I owned years ago.

jda2000

This is not a Lexus only problem.
Is a good practice to turn off the AC a few blocks before you reach your destination and leave the fan on. This dries out the evaporator behind the dash. Wet evap leads to mold overgrowth over time.

I've been doing on all the cars I have owned down here in humid Florida, and I don't have that problem with the odor.

jollick

Part of the reasoning for re-circulation is to remove humidity from the air. Allowing fresh air in is letting humidity in.

lamikela1

Here is an excerpt from the factory repair manual. This should clear this up.

8. AUTOMATIC RECIRCULATION CONTROL

(a) When automatic recirculation control is operating, the air conditioning amplifier assembly automatically changes the air inlet mode to FRESH or RECIRCULATION mode based on signals from the smog ventilation sensor, ambient temperature sensor (thermistor assembly) and room temperature sensor (cooler thermistor) when AUTO air inlet mode is selected.

(1) The air conditioning amplifier assembly detects harmful elements (CO, HC and NOx) based on a smog ventilation sensor signal and automatically switches the air inlet mode to RECIRCULATION mode to prevent such harmful elements (CO, HC and NOx) from entering the cabin.

(2) The air conditioning amplifier assembly detects cabin temperature based on a room temperature sensor signal and automatically switches the air inlet mode to RECIRCULATION mode to prevent the cabin temperature from becoming too high.

(3) The air conditioning amplifier assembly detects the outside temperature based on an ambient temperature sensor signal and automatically switches the air inlet mode to FRESH mode to prevent the windshield from fogging up.

NOTICE:

The smog ventilation sensor cannot detect elements such as the smoke from a bonfire or factory exhaust, foul or animal odors, and dirt or dust particles. Therefore, the air inlet mode is not switched automatically in accordance with those elements.

lesz

Actually, I don't believe that is the case. While more humidity may be allowed into the cabin in fresh air mode, the compressor is also operating a larger percentage of the time in fresh air mode The result should be that, in either mode, humidity levels should ultimately be about the same, but, with the compressor running more in fresh air mode to achieve the same temperature and humidity levels, fuel economy will be marginally lower; however, any stale air that otherwise would be accumulating in the cabin will have a chance to be replaced, which is not the case in recirculate mode. .

Until a few years ago, automatic AC systems defaulted to fresh air mode unless the outside temperature was above about 90 or 95 degrees, but the auto manufacturers realized that they could get marginally higher EPA fuel economy ratings by having the systems default to recirculate when the outside temperature was above about 75, and I doubt that it is a coincidence that that is also when the owners of many vehicle models started to complain about stale air quality.

I'll also not that, on a very hot day when the outside temperature is, say, 95 degrees and the car has been parked in the sun, the car will actually cool off much faster in fresh air mode than it will in recirculate mode. If the system is using recirculate mode, the AC needs to lower the cabin temperature from the 120 degree or higher temperatures in the cabin down to 70 or 75 degrees or whatever temperature the system is set to. But, in fresh air mode when the AC system is drawing in outside air, which may be 30 degrees or more cooler than the air inside the car, the AC system does not need to lower the temperature of the air nearly as much in fresh air mode as it needs to in recirculate mode.

Arty101

Good info. Thanks for the clarification.

ESh888

@Align - Increase the sensitivity of the smog ventilation sensor. It worked form me. I found the setting on the on-screen menu, I think the setting is in the custom setting screen (I’m not too sure...I would have to go to the car and check).

FYI - To save some money I replaced my in-cabin air filter with an aftermarket Fram filter. In my opinion, it was a bad idea, I could tell the difference. I kept it for a week and replaced it with a Lexus in-cabin filter.