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P0420

Discussion in 'Newbie Forum' started by Randy Stein, Mar 30, 2023.

  1. Randy Stein

    Randy Stein New Member

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    Vehicle:
    2006 Prius
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    Two
    Hi guys
    I’m really confused on this code. I know it refers to the catalytic converter low efficiency, I’m sure its operating percentage is just under the passing line , from what I have read is when the cat is not working correctly, you would see mpg low , low pick up speed , no rotten egg smell , actually I have the complete opposite
    I have , fantastic pick up speed, I get 49- 51 mpg , no smell , all I have is the code. It’s a 2006 with 230 k milage on it. Maybe it’s a exhaust leak ? Maybe cataclean will work because it’s just under that percentage, any input will help. I’m being stubborn on not just giving in to change out the cat ?
     
    #1 Randy Stein, Mar 30, 2023
  2. bisco

    bisco cookie crumbler

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    #2 bisco, Mar 30, 2023
  3. PriusCamper

    PriusCamper Senior Member

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    I always first ensure new spark plugs and engine air filter is covered, then MAF sensor and throttle body cleaning is taken care of before going after PO420 more directly... Also buying a bad tank of gas can cause this problem.

    And if you are still using the original OEM cat and can't get it fixed, it can be sold for more than $1K just for the precious metal inside and these are the aftermarket cats we recommend that are only $100, but they might not ship one to New York and you'll need to ship it to a friend out of state: https://www.ebay.com/itm/193690871378 Also maybe vehicle inspection for registration renewal challenges, but that's only been mentioned in California
     
    #3 PriusCamper, Mar 30, 2023
  4. douglasjre

    douglasjre Senior Member

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    ----USA----
    What will you do regarding New York State emissions/inspection?
     
    #4 douglasjre, Mar 30, 2023
  5. Classic Car Guy

    Classic Car Guy Active Member

    Joined:
    Dec 23, 2018
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    Location:
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    Vehicle:
    2007 Prius
    Model:
    II
    Mine just lit up last night as I was pulling in the driveway.
    I put the scan tool today and its says:
    P0420 01
    P0420 02
    I'm also a victim of that stolen catalytic converter and replaced mine with aftermarket 2 years ago. At first time replaced, it was running nicely with above 45mpg on the screen (more than what I use to have). after a year it went down to 41-43 mpg. My car eats a 1/4 of a quart after 4500-5000 miles of driving with 151k miles, 07 prius..
     
    #5 Classic Car Guy, Sep 22, 2023
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