want to disable automatic switching between recirc and outside air mode

I'm confused on one point.
Respectfully, where do you believe the air that enters your car is coming from on an extended drive? No car is air tight--nor do you want it to be. It seems to me that the air that you're breathing is, in the long run, coming from the same roadway area that the HVAC system draws from.
How can it be cleaner?
What makes the freshly drawn in air dirtier than what creeps in anyhow?

 

I'm with you on this one. Sometimes when I get behind certain vehicles, my eyes just seem to water until I either back away from them or pass them. Now if everyone was driving Prius' or EVs, your problem would be solved.

 

Yes and when you see a stinky car ahead press the Recirc button on the right steering wheel spoke. That's what it's there for, you don't have to look away.

I pulled up behind an old 2-cycle scooter at a light. I hit the button, but when we started pulling away I still smelt it.
Boy, he dealt it.... That is such a pollution producer.....
I believe it's a Fed thing that even on Recirc you still have 10% fresh air flow. At least it's filtered on the Prius.
And the activated charcoal ones are available but they supposedly don't last long.

Asthmatic, and all,
That Microfilter/Clean Air button is just an Ion Generator. There is no extra filtering taking place. It's in the Manual.
A Sharp® Ion Generator is in the driver's vent. It only makes dust stick to surfaces.
And negative ions are an asthma trigger for some people. Look it up.
That button can be making you ill.

 

The OP's 2012 Prius 3 does *not* have the ionizer. Even if he did, the ionizer is passive anyhow (constantly on, not controlled by the filter button).
The filter button does some good in that it lets less outside air in than recirc does (during the 3 minutes it's in operation).

Please read the owner's manual.

 

Bill, We've covered this ground before:
Vent in Winter only works for a minute | PriusChat
Stop spreading the FUD.

 

Interesting, they dropped the ionizer for '12.
I wonder why?

I disagree about the ionizer function, read the vague manual page on that goofy button.
There is no extra filter. It would have to be changed if there was one.

I use mine all the time. I hit it, turn off the AC, switch to fresh air (sometimes it comes up with fresh and ionizer),
and I then bask in the magical fumes !!

Let's hear some opinions on what the Plasmacluster has done for you since buying a Prius !!!!

Me? I need haircuts more often and I haven't had a bad dream since using my Plasmacluster button!!

 

They also never offered it on other than the IV and the V.

The button has nothing to do with the ionizer.

I give up.

 

OK, sorry, I don't have my manual with me to quote from. Maybe '10 manuals describe this system differently.
But if there is a "Micro Filter" somewhere in the system, wouldn't it need changing? Where is it located in the maintenance manuals?

And, I sometimes hear the a snapping static electricity sound when using my "Plasmacluster" button.
Just like my manual said I would, along with possible radio interference.

What's FUD?

 

The filter button circulates thru the same filter that the system uses normally, but does it at higher fan speed with the AC engaged and the outside air closed off entirely.
It probably makes your ionizer snap more because of the higher speed thru your ionizer vent (the one on the far left with the logo next to it).

In a word, FUD is disinformation.

 

ccs, all,

Tell me this isn't a questionable page from the '10 manual.

3-1. Using the air conditioning system and defogger
■Micro dust and pollen filter
●In order to prevent the windows from fogging up when the outside air is
cold, the following may occur.
• Outside air mode does not switch to recirculated air mode.
• The air conditioning system operates automatically.
• The operation cancels after 1 minute.
●In rainy weather, the windows may fog up. Press .
■When Eco Driving mode is on
●If the outside temperature exceeds a preset temperature, the system will
switch to recirculated air mode.
●The effectiveness of the air conditioning will be lower than normal.
●The fan speed level drops below the normal rate.
■Plasmacluster™* (if equipped)
Plasmacluster will operate in conjunction with the air conditioning fan motor
when it is turned on.
This air conditioning system adopts plasmacluster technology, which helps
to keep good air quality in the cabin by emitting positive and negative ions
through the driver’s side vent.
A slight noise may be heard during operation. This is not a malfunction. Also,
static electricity may be discharged near the driver’s side vent due to the
high voltage used to operate the system.
To clean the driver’s side vent, turn the system off and wipe the vent using a
soft cloth.
*Plasmacluster technology is manufactured under license from the SHARP
Corporation.
“Plasmacluster™” is a trademark of the SHARP Corporation.
■Air conditioning odors
●During use, various odors from inside and outside the vehicle may enter
into and accumulate in the air conditioning system. This may then cause
odor to be emitted from the vents.
●To reduce potential odors from occurring:
• It is recommended that the air conditioning system be set to outside air
mode prior to turning the vehicle off.

The problem is in the interpretation of the manual. (You do find some Engrish in this manual)
I think they mean that switch is the Plasmacluster switch. See where they tell you to clean the driver's vent?

Where do you get your opinion on this switch's function, other than the name on the picture, page 270?

And, I'm pretty sure when you are in Recirc the outside air filter is not in the circuit.
When I changed my filter it was only open to the outside air on the dirty side.

 

And here is the vague page from the '12 manual. The "Plasmacluster" name is no longer used.
There is no description of what that button does.....


3-1. Using the air conditioning system and defogger
■When is selected for the air outlets used
For your driving comfort, air flowing to the feet may be warmer than air flowing to the upper body depending on the temperature setting.
■Micro dust and pollen filter
●In order to prevent the windows from fogging up when the outside air is
cold, the following may occur.
• Outside air mode does not switch to recirculated air mode.
• The air conditioning system operates automatically.
• The operation cancels after 1 minute.
●In rainy weather, the windows may fog up. Press .
●Condensation may appear on the windows if this mode is used in abnormally high levels of humidity.
●Pollen will be collected by the filter even when micro dust and pollen filter
mode is OFF.

 

I'll study my 2011 manual this evening when I'm home.

 

It's vague.
Every thread I checked it says this is vague.

We may never get the truth unless Toyota chimes in.

I'm just trying to help people dealing with asthma and the fact that ion generators can be a trigger.


I read it as when this silly button is pressed the ion generator comes on for 3 mins.

I am fairly certain when in Recirc the air is not passing through the outside air filter. You are just rebreathing the cabin air with ~10% fresh being added due to Federal Regs.

 

Per my manual I have this:

[after pressing the filter button] Outside air mode switches to recirculated air mode. Pollen is removed
from the air and the air flows to the upper part of the body.
Usually the system will turn off automatically approximately 3 minutes
later.
To stop the operation, press [the button] again. The button they refer to is labeled as the miro dust and pollen filter button.

Note that there's no mention of the ion system. This is partly because the II and the III do not have the ion system, yet we have the button.

As to your quote: Plasmacluster will operate in conjunction with the air conditioning fan motor
when it is turned on.I read that to mean that it will operate when the fan motor is turned on. Nothing more, nothing less.

The vast majority of the 2010-2011 Prius cars do not have the plasma cluster system and they all have this filter button function.

I've got to do dishes and mow the lawn. I'll look in the service manual for information later on.

 

From what I can decipher from the factory repair manual AC diagram and parts illustrations, there is a valve before the blower that selects outside or recirculated air, then the blower blows through the filter so the filter is always in the loops. I can't quite be 100% sure, but that's how it looks.

 

From the repair manual:

MICRO DUST AND POLLEN FILTER MODE CONTROL​

(a) When the micro dust and pollen filter mode switch is pressed, the micro dust and pollen filter mode control is activated.
(b) Then, the air vent is switched to the FACE mode and recirculated pollen-free air flows in the area around the upper part of the bodies of the driver and front passenger.
(c) When the micro dust and pollen filter mode switch signal is input to the A/C amplifier, the A/C amplifier controls the compressor with motor assembly, air inlet control servo motor, air outlet control servo motor and blower motor as shown in the timing chart below.
(d) This control usually operates for approximately 3 minutes. However, when the outside temperature is low (5°C (41°F) maximum), it will operate for approximately 1 minute.
(e)

After this control stops operating, the A/C amplifier controls the air conditioning system using AUTO mode.​

PLASMACLUSTER (ION GENERATOR) CONTROL (w/ Plasmacluster (Ion Generator))
(a) General:
(1) A Plasmacluster (ion generator) is provided inside the air duct of the side register on the driver seat side to improve the air quality and comfort in the cabin.
(2) This generator is controlled by the A/C amplifier and operates in conjunction with the blower motor.

NOTICE:
* The Plasmacluster (ion generator) uses a high voltage, which is hazardous. Therefore, if the Plasmacluster (ion generator) requires repairs, be sure to have them done at a TOYOTA dealer.
* Do not apply any type of spray (such as a cleaning solvent or hair spray) or stick any foreign matter into the Plasmacluster ion outlet, as this could cause improper operation or a malfunction.
* After use, dust may accumulate around the side register on the driver seat side. If this occurs, press the OFF switch on the A/C control assembly to stop the blower motor before cleaning the area.
*
It is normal for the Plasmacluster (ion generator) to emit a slight sound during operation. This sound is created when electrons collide with the electrode while Plasmacluster ions are being generated.

The Plasmacluster (ion generator) produces positive and negative ions from the water molecules (H2O) and oxygen molecules (O2) in the air, and emits them into the air. These ions reduce airborne germs.

 

More questions....

How do you have a 'micro filter' if there is no ion generator on some model levels?
There does not seem to be an actual 'micro filter' anywhere in the system.
The ion generator makes the dust cling to surfaces and we are told to clean up the driver's vent....

Again, I just wanted to point out to the OP that if it is an ion generator that Toyota is calling a 'micro filter',
it might not be the way to go for asthma sufferers.

And ccs,
I like to think that I am not a purveyor of FUD.
I'm one of the guys here that beats the drum for facts and references not opinions.

I don't make this stuff up. And when I do, I'm trying to be funny.
Like,,, why would Toyota adopt this questionable technology from Sharp?
To some people Ion Generators are a joke.
But to other people the perceived benefits are amazing !!!!

 

The (one and only) paper filter *is* the microfilter that is being used in Micro Dust and Pollen Filter Mode.

According to the service manual references above the ion generator is supposed to kill germs.

Sorry about my FUD comment. I hope the service manual clippings have been helpful.

 

Fear, uncertainty, and doubt