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Gen II Air Cleaner Cap Subassembly - Charcoal Filter?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Zedhomme, Sep 8, 2013.

  1. Zedhomme

    Zedhomme Member

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    Looking for a Prius Jedi who knows if what looks like a charcoal filter in the air cleaner cap which doesn't have any air flow through it does anything important or anything at all.
     
  2. jadziasman

    jadziasman Prius owner emeritus

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    Heck, it must serve a purpose, otherwise Toyota wouldn't have added it to the cover.

    And, contrary to what you stated, intake air enters the left side of the air filter housing, goes through the air filter, and then travels through the "charcoal filter" and crosses over to the right side of the cover through ports at the upper part of the cover.

    My guess is the permanent filter is there as a fail-safe device just in case someone forgets to install the air filter.
     
  3. Paradox

    Paradox Prius Enthusiast / Moderator
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    Moved to the proper forum
     
  4. Zedhomme

    Zedhomme Member

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    I took another look. I never really took that close a look except to check that it wouldn't come out of the housing and that It can't be ordered separate from its housing.
    You're right. It does go through that after the air filter, and Toyota wouldn't charge $100 for it if it didn't do something valuable, right? Maybe it neutralizes acidic air from pollution so it won't corrode the throttle parts and MAF.
     
  5. AzWxGuy

    AzWxGuy Weather Guy

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    I think it is an integral part of the zero-emission system, catching any fumes that might try to escape from the intake manifold when the engine is off or possibly when it is cold spinning to use up some of the HV battery charge when it is full. I would like to see what a new one looks like so I could compare it to mine and maybe stop worrying about restricted airflow due to contamination with fine particulates that have managed to get past the replaceable air filter. Since I purchased the vehicle used, I have no idea what a new one looks like. A visit to my local Toyota parts department might be in order, hmm?
     
  6. jadziasman

    jadziasman Prius owner emeritus

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    Zedhomme likes this.
  7. RRxing

    RRxing Senior Member

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    ^^^ Correct.
     
  8. Zedhomme

    Zedhomme Member

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    Thanks for doing the research. Wonder if it ever needs to be changed like the spark plugs to extend the emission control warranty? Required under the terms of the Emission Control Warranty. Does not apply to PZEV Prius in California, New York, Massachusetts, Maine and Vermont. For Gen II Prius, replacement interval is 150,000 miles, although Toyota maintenance says 120,000.