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P0420 + Red Triangle Disappeared after 30 min

Discussion in 'Gen 2 Prius Technical Discussion' started by Michikazu, Jul 25, 2017.

  1. Michikazu

    Michikazu New Member

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    2006 Prius (gen 2)
    201,000 Miles
    Serviced by Toyota, never missed an oil change
    Orange County, Ca

    Last night after leaving a friends, about 1 min into my drive I got an explosion of dash lights, the car shut down and turned off. (12V battery is fine) Red Triangle, Check Engine, The works. Pulled over and ran the OBD Fusion app and came back with P0420 and P3190.

    Did my research, Cat or O2 sensors, etc. Got car towed home, decided to try again before going to bed and everything was fine, no dash lights. Re-ran the Diagnostics, and cleared the codes to see. SO far so good.
    Anyone else have this weird issue?
     
  2. 'LectroFuel

    'LectroFuel Senior Member

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    From what I've researched, P0420 is just the O2 sensors in the Cat. P3190 is loss of engine power. It might have just been a malfunction and you needed to restart your car.
     
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  3. Michikazu

    Michikazu New Member

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    Thats good to hear. Just drove it around for 15 min, had the Red Triangle turn off and on (Very fast)
    twice coming up hill, Im wondering if its low on oil?
     
    Freeus5 likes this.
  4. 'LectroFuel

    'LectroFuel Senior Member

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    That happened on my gen 2 several years ago when I went down a hill. Could be the gas tank or a loose HV battery connection. I'm not an expert, but @Patrick Wong is so maybe he'll help.
     
    Michikazu likes this.
  5. fotomoto

    fotomoto Senior Member

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    Wondering? You should know if it is. ;)
     
    valde3, m.wynn, 'LectroFuel and 3 others like this.
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    1. Check the engine oil level, do not guess.
    2. Clean the throttle body interior now.
    3. When were the iridium spark plugs last replaced? If you have no knowledge that was done, do that now.
    4. Work on saving sufficient funds to replace the catalytic converter if you expect to renew your auto registration in CA.
     
  7. Michikazu

    Michikazu New Member

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    Thanks guys!!
     
  8. 05PreeUs

    05PreeUs Senior Member

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    It is WELL known that Toyota and Subaru log P0420 codes for even the slightest loss of catalytic converter efficiency, WELL before this loss can even be detected by a typical emissions analyzer. There are any number of causes for the P0420 DTC, only one of which is actually a failed or failing "cat".

    Common things that can cause P0420 are:
    - oil burning (wear, bad pcv valve, overfull of oil, etc)
    - exhaust leak
    - lazy O2 sensor (rear)
    - worn out WBO2 sensor (AFR sensor, front)
    - poor air/fuel metering
    - tune up
    - defective sensors (other than O2/WB O2)
     
  9. Freeus5

    Freeus5 Junior Member

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    My red triangle goes on when my 06 is low on oil.
     
  10. dolj

    dolj Senior Member

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    Old thread (I know) but if you wait that long to top up your oil, you're damaging your car. Likely an oil burner. Expect catalytic converter problems.
     
  11. Freeus5

    Freeus5 Junior Member

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    It has been burning oil like this for a long time, maybe 2 years? And then the cat converter got stolen, and replaced TWICE. But maybe that is the reason I have the p0420 on now? Because the second cat converter didn't trip the check engine light until I hit a big puddle on a highway.

    I mean I have to top off the oil fairly often.
     
    #11 Freeus5, Jan 2, 2023
    Last edited by a moderator: Jan 3, 2023
  12. Patek111

    Patek111 New Member

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    Hi I just replaced my hybrid battery and got the same p0420 code how can I check for HV battery connection problem is there a diagram/ video?
     
  13. mr_guy_mann

    mr_guy_mann Senior Member

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    P0420 is a code set by the ECM indicating that the catalytic converter efficiency is below acceptable limits. It has nothing to do with the hybrid drive system.

    Use the search feature to check the Gen 2 forums for P0420. I have made a number of posts about what to check before condemning the cat.

    Posted via the PriusChat mobile app.
     
    Brian1954 likes this.