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P0101 + P0420 -- How linked are these?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by maleko, Jul 2, 2024 at 7:18 AM.

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  1. maleko

    maleko Member

    Joined:
    Feb 1, 2017
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    Location:
    Central FL
    Vehicle:
    2008 Prius
    Model:
    Base
    While performing my recent inverter swap I went ahead and replaced my PCV valve (old one was still rattling, albeit a bit gunked up), cleaned my throttle body, and sprayed my MAF with the same MAF cleaner I've been using at every oil change the past many years without issue.

    Prior to my inverter failure, I would not be surprised to find the P0420 catalytic code given my Prii's oil consumption habit and recent clogging issues, but I never had the P0101 previously. I am not in a smog state and don't care about the catalytic at this point, but I don't like the idea of the MAF code P0101 hanging around and would prefer to at least sort that out if possible.

    1.) What are some tests I can do to verify some of the issues at hand and make sure my MAF sensor, O2 sensors themselves are working as expected? (I have TechStream.)

    2.) What are the effects / risks of running with P0101 longer term if it comes to it?

    3.) How likely is it the P0101 is linked to the P0420 rearing its head now?

    4.) Will an O2 sensor bypass potentially work around any of the above issues and get the engine to at least provide normal fuel / power / trims / etc? (I understand it would not actually fix the underlying issue(s) at hand.)

    5.) Can an exhaust header leak (block side gasket and/or mating donut to catalytic section of exhaust) cause any of these issues?

    6.) Will cleaning / replacing / straight piping / punching out my catalytic help any of the above aside from the obvious reduction in flow restriction? (I am considering cleaning my cat again and/or punching it out. I also have a welder and tools that I could straight pipe it if I really wanted to I guess...)
     
    #1 maleko, Jul 2, 2024 at 7:18 AM
  2. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
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    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    What you do with your converter is not punch holes through it You cut the pipe off one end of it if it's not a bolt in which it's not I'm pretty sure they're all weldins and made up pipes so you have to come up with a way to gut the cat or put a straight pipe there if you can get your muffler guy to weld you up a pipe it looks like your catalytic converter pipes then you just weld that into the car and forget about the converter I have an '09 just like that sitting right here in the parking lot and the other three cars all have their cats installed and no codes and have been that way for $300,000 plus miles All those three cars are original cats. The 09 has had the PO420 code since when I bought it 5 years ago I'm in a non-emission state I whacked out the cat left the O2 sensor bung in place and put the pipe right back in the car I have a fancy stainless steel 90° spacer for the O2 sensor I seem to never get around to install The PO420 does not affect my gas mileage it's been basically the same the whole life of the car I know the original owners I've never had the other code you're having and if that's for the MAF sensor given the fact that you clean it every oil change maybe it's just time to replace or get one off of another junkyard car I personally haven't had that code I do not blast my MAF sensor every oil change maybe twice a year or once a year at best I don't even know what the other code is I would have to go look it up. But I am in a non emission state.
     
    #2 Tombukt2, Jul 2, 2024 at 8:00 AM
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