1. Attachments are working again! Check out this thread for more details and to report any other bugs.

P0420 check engine light cat questions

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Laman012, May 22, 2019.

  1. Laman012

    Laman012 Junior Member

    Joined:
    May 22, 2019
    10
    2
    0
    Location:
    91786
    Vehicle:
    2004 Prius
    Model:
    N/A
    my 2004 Prius is throwing P0420. I was told that this means that I need to replace the catalytic converter. The explanation I got is that since it is a high mile car (>200,000) the engine is burning oil and clogging the cat.

    Replacing the cat at the dealer will run me $$$. Are there any alternative options? Are there aftermarket options that aren't from Toyota?

    My car is registered in CA, but I currently live out of state; however, I plan on moving back to CA soon. Could I have the cat replaced out of state, then move back to CA with it?

    Thanks!
     
  2. Laman012

    Laman012 Junior Member

    Joined:
    May 22, 2019
    10
    2
    0
    Location:
    91786
    Vehicle:
    2004 Prius
    Model:
    N/A
    So today I changed the PCV valve, the spark plugs, and cleaned the mass air flow sensor and throttle body. The check engine light went off after I drove it around the block and it's running better than ever.
     
    landspeed and Raytheeagle like this.
  3. Dxta

    Dxta Senior Member

    Joined:
    Nov 7, 2016
    1,932
    766
    0
    Location:
    Lagos
    Vehicle:
    2008 Prius
    Model:
    II
    Might have worked in the short-term, consideriythat you for to do some drive cycles, to see if that cosw lops up again.
     
  4. landspeed

    landspeed Active Member

    Joined:
    Feb 25, 2007
    351
    198
    0
    It is reassuring that the light went off, because it means that one of those things you fixed (or a combination of all of them) sorted the code that usually means 'replace the cat'. Well done and hopefully it lasts a good while. I will put what you did on the list of things to do on my car (I get P0420 constantly!)