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06 swp Outback
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Discussion Starter · #1 ·
I have an 06 outback an noticed this time that there is a filter or more like a mesh filter behind the air filter.

Anyone else notice this? it doesn't seem serviceable. has anyone removed it or tried to find a replacement?

Thanks

Joe
 

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I have that mesh screen downstream (between air filter and MAF) from my air filter as well, but mine is an '07, and I don't think it has a PZEV engine, just a regular 2.5.
At least it doesn't have the PZEV badge on my rear hatch like the others do.
Anyone else think they know what this secondary filter/mesh screen is?
 

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keeps stuff out - in the past other cars I've had - had similar pieces of material I simply washed them out occasionally like every 50K and put them back in. Best guess is that its there to keep debri from getting in there when you swap out the standard filter.

Has nothing to do with PZEV - PZEV is related to more precise fuel monitoring and exhaust systems that are more capable of scrubbing the exhaust. Think of a PZEV as a slightly more intelligent car regarding fuel mixture and exhaust output.
 

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So therefore my engine is a PZEV?
How often do these filters need replacement then?
I know carbon loses its adsorption capacity pretty quickly in any (contaminated) environment, so I don't think these things would be very effective after a month or so. It looks to me like it would just further restrict airflow.
 

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Subaru has been building Legacys and Outbacks meeting PZEV specs going back to at least 2005. There was no marking on the outside on these earlier version, but the engine emissions label under the hood would indicate that the car meets these more stringent (California) requirements. They were sold in many states, not only those requiring CA emissions control.
 

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So therefore my engine is a PZEV?
How often do these filters need replacement then?
I know carbon loses its absorption capacity pretty quickly in any environment, so I don't think these things would be very effective after a month or so. It looks to me like it would just further restrict airflow.
It's not meant replacable unless you replace the air cleaner box.

My '07 has that secondary filter also. No PZEV badges, but my car was included in the recall to re-flash the ECM on PZEV cars.
 

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01 VDC, 05 R Sedan, 06 BAJA EJ257
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@Carl86 That screen is there to catch media that may get in to the air tube, like pieces of the air filter. You can take it out if you want. It may speed up the air flow to the intake. You'd be removing a restrictor.
 

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Has anybody had a consequence by removing that filter?
@Carl86 That screen is there to catch media that may get in to the air tube, like pieces of the air filter. You can take it out if you want. It may speed up the air flow to the intake. You'd be removing a restrictor.
Not clear what "screen" means in this case. But, as noted earlier in this thread, the PZEV's have a second media behind the regular air filter. It is not a filter in the sense of catching particles coming into the engine. Rather, it's a charcoal element that will absorb gas fumes that can appear in the intake manifold when the engine is turned off. Instead of the fumes making their way out to the atmosphere through the intake duct engine air filter, they are trapped at the charcoal element. When the engine is restarted, the incoming air draws them into the engine. This is the same principle as the charcoal canister that controls gas fume emissions from the fuel tank.

Removing the charcoal element would not itself cause a P0420.
 

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Not clear what "screen" means in this case. But, as noted earlier in this thread, the PZEV's have a second media behind the regular air filter. It is not a filter in the sense of catching particles coming into the engine. Rather, it's a charcoal element that will absorb gas fumes that can appear in the intake manifold when the engine is turned off. Instead of the fumes making their way out to the atmosphere through the intake duct engine air filter, they are trapped at the charcoal element. When the engine is restarted, the incoming air draws them into the engine. This is the same principle as the charcoal canister that controls gas fume emissions from the fuel tank.

Removing the charcoal element would not itself cause a P0420.
Thanks for the explanation.
but i have a doubt, if the charcoal element is some restrictive, could the eco be programe for running the engine with that restriction and if removed... maybe the downstream o2 is receiving data that the catalytic is not good because the engine is working with less restrictive intake?

is there a possibility?

Thanks
 

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2020 Onyx
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Many people have been removing those charcoal filters on BMW's and Subarus for years with no negative consequences. If your car threw a code after removing that filter, either you inadvertently did something else in the process, or it was pure coincidence.
 

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a mesh is nice when a mouse has eaten up the paper, and the bits have gotten sucked down into the intake. in my case stuck at the butterfly,...and I could shop-vac it clean, = car ran fine for a mile, then it would run to wide open uncontrolably when started. (glad I had a used filter on the shelf at the time)

after that I only bought ones with a metal mesh before the paper.
 
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