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P0420 Worth replacing catalytic converter a 2nd time? 297k

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by 2ndgenbestgen, Aug 11, 2022.

  1. 2ndgenbestgen

    2ndgenbestgen New Member

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    First time sometime stole it, did a cheap after market replacement, now it's throwing P0420. Emissions isn't a concern. Fuel economy has been unaffected.

    Any other issues that could arise from this that would make it worth worrying about? Thanks.
     
    #1 2ndgenbestgen, Aug 11, 2022
  2. mr_guy_mann

    mr_guy_mann Senior Member

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    The only concern I would have is that if the light is on all the time, you won't be able to know if some other fault occurs.

    Posted via the PriusChat mobile app.
     
    #2 mr_guy_mann, Aug 12, 2022
  3. Tombukt2

    Tombukt2 Senior Member

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    Mine has been on for 2 years I still have the original cat in this '09 that I'm driving and it's been throwing this code but I have not changed both sensors with a decent set of the proper numbers in the right place when I first got the car the light was not on and the guy said he had never seen the light. And he drove this car all the $200,000 miles except 15 of it. So I'm going to try the sensors first and see if that cleans the mess up I really have trouble believing that there would be different amounts of flow rates in these converters versus another two z converter like in a Corolla but I know they're heating problems and other things so we will see
     
    #3 Tombukt2, Aug 12, 2022
  4. 2ndgenbestgen

    2ndgenbestgen New Member

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    Maybe for you it may just be sensors.
    If it's a bad catalytic converter you'll start to smell sulfur more. If you don't smell anything then maybe it's just that.
     
    #4 2ndgenbestgen, Aug 18, 2022
  5. mr_guy_mann

    mr_guy_mann Senior Member

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    A sulphur smell is likely caused by the fuel mixture being too rich (too much fuel)- that causes the cat to spit out sulphur dioxide along with other "bad" gases.

    I would be testing the A/F and O2 sensors.

    Normal exhaust- even with a dead cat- doesn't smell like much of anything (unless your engine burns a lot of oil).

    Posted via the PriusChat mobile app.
     
    #5 mr_guy_mann, Aug 19, 2022
  6. 2ndgenbestgen

    2ndgenbestgen New Member

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    Interesting. the exhaust in this car smells horrid, and the code is p0420. Burns a lot of oil though, I've read it's that oil burn in a high mileage Prius that ruins the catalytic converter.

    I see some websites shilling " CRC Turbo and Intake Valve Cleaner". Is it snake oil?
     
    #6 2ndgenbestgen, Aug 19, 2022
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