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P0420

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Suhkoi2, Jan 25, 2016.

  1. Suhkoi2

    Suhkoi2 New Member

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    Catalyst System Efficiency Below Threshold. That's all the computer says. This is for the check engine light, Just reset it again and kept driving but got home and got this code P0420.

    Wondering is it just the catalytic converter is a bit dirty (From putting in diesel).

    Will try do a clean with water next week any idea if this will help.

    Thanks for reading.
     
    #1 Suhkoi2, Jan 25, 2016
  2. bisco

    bisco cookie crumbler

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    you put diesel in your prius?
     
    #2 bisco, Jan 25, 2016
    anonymous likes this.
  3. Suhkoi2

    Suhkoi2 New Member

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    Bought car broken fixed her up,first after clearing hybrid system failure huge amount of smoke.

    Thats the reason I'm hoping a clean will do.
     
    #3 Suhkoi2, Jan 25, 2016
  4. bisco

    bisco cookie crumbler

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    all the best.(y)
     
    #4 bisco, Jan 25, 2016
  5. Merlock

    Merlock New Member

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    I have the same code and I'm curious about "things to try before spending £1200 on new CAT.

    Any advice?
     
    #5 Merlock, Feb 17, 2017
  6. Sam Spade

    Sam Spade Senior Member

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    Spend 100 on a shop diagnosis.
    Then shop around for "3rd party" replacement cats; muffler shops probably know.
    This is unless you live in a place where OEM cats are required.......like California USA.
     
    #6 Sam Spade, Feb 17, 2017
  7. jerrymildred

    jerrymildred Senior Member

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    I can see how diesel would foul the cat. Whether it will clear out on its own, I don't know, but I'd think it might if it gets hot enough. I just tried searching for "what will diesel do to a catalytic converter" and came up with nothing that looked helpful. Hope you can get it fixed without a big bill.
     
    #7 jerrymildred, Feb 17, 2017
  8. Sam Spade

    Sam Spade Senior Member

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    Year old thread but.......
    If the partial diesel mixture allowed the engine to actually run long enough to belch out black smoke, that also means that some raw diesel fuel likely ended up IN the cat......and unburned fuel in there is likely to cause a FIRE when the engine actually runs again.
     
    #8 Sam Spade, Feb 17, 2017
  9. jerrymildred

    jerrymildred Senior Member

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    @Sam Spade , I see that now. I saw the recent posts and didn't got back to see how old the older ones were. <blush> :oops:
     
    #9 jerrymildred, Feb 17, 2017
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