Thread: CAT or O2 Sensor

Results 1 to 8 of 8

Hybrid View

Previous Post Previous Post   Next Post Next Post
  1. #1 CAT or O2 Sensor 
    SE Level Member trenaro's Avatar
    Join Date
    Feb 2009
    Location
    KC
    Posts
    52
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    Hey Guys,

    my 01 GT is throwing a PO420 code. Can't seem to figure out if it's the CAT or O2. Car has been running a little sluggish with poor fuel mileage.

    Any thoughts?

    Thanks

    T
    Reply With Quote  
     

  2. #2 Re: CAT or O2 Sensor 
    TDCRacing
    Guest
    Someone had this code on here just recently. And is the first time I have ever heard of this. They said they changed out the o2 sensor and it went away. I think it will be back though.



    I have never seen an o2 sensor code that said catalist system low effeciency. And have seen a lot of o2 sensor codes.


    I think you're cat is getting clogged and you may need a new one soon. And that is also why it is sluggish and you are getting poor fuel economy. That o2 sensor does not do anything with fueling in the car. It is only there to see if the cat is working properly. THAT IS IT!

    And that's what is is doing now.
    Reply With Quote  
     

  3. #3 Re: CAT or O2 Sensor 
    GrandPrix Junkie Sabrewings's Avatar
    Join Date
    Dec 2007
    Location
    Barksdale AFB, LA
    Posts
    4,879
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    Quote Originally Posted by TDCRacing View Post
    Someone had this code on here just recently. And is the first time I have ever heard of this. They said they changed out the o2 sensor and it went away. I think it will be back though.



    I have never seen an o2 sensor code that said catalist system low effeciency. And have seen a lot of o2 sensor codes.
    I've seen this a lot. Especially when I worked for a dealer. The O2 sensor goes bad but not to the point that it trips its own code. It shows false readings that makes the PCM think the cat is bad.

    If he has a stock cat, it's the O2 sensor.
    2004 Impala LS - got some mods sold!!!
    2009 Subaru Impreza WRX STI

    NAIOA moderator Still Imp'n, just in a different Imp.
    Reply With Quote  
     

  4. #4 Re: CAT or O2 Sensor 
    TDCRacing
    Guest
    Quote Originally Posted by Sabrewings View Post
    I've seen this a lot. Especially when I worked for a dealer. The O2 sensor goes bad but not to the point that it trips its own code. It shows false readings that makes the PCM think the cat is bad.

    If he has a stock cat, it's the O2 sensor.




    Do you think that it is actually the 02 going out more of the time than it actually being a bad cat? Especially seeing that these cars usually have a pretty good amount of miles on them? Good info non the less.
    Reply With Quote  
     

  5. #5 Re: CAT or O2 Sensor 
    GTP Level Member Scimmia's Avatar
    Join Date
    Jun 2008
    Location
    QCA, IA
    Posts
    1,054
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    Are you running a stock cat? If not, many aftermarket cats throw this code all of the time, they just don't work as well as OEM.

    If you are stock, hopefully you're under 120,000 mi, because GM extended the warranty on the cat on the 01-02 L36 because of a defect that could block it. Take it to the dealership for a free fix.
    2001 Buick Regal LS - Almost Stock
    Reply With Quote  
     

  6. #6 Re: CAT or O2 Sensor 
    SE Level Member trenaro's Avatar
    Join Date
    Feb 2009
    Location
    KC
    Posts
    52
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    Thanks guys
    Reply With Quote  
     

  7. #7 Re: CAT or O2 Sensor 
    TDCRacing
    Guest
    Quote Originally Posted by Scimmia View Post
    Are you running a stock cat? If not, many aftermarket cats throw this code all of the time, they just don't work as well as OEM.

    If you are stock, hopefully you're under 120,000 mi, because GM extended the warranty on the cat on the 01-02 L36 because of a defect that could block it. Take it to the dealership for a free fix.


    Awesome info about the recal. Did not know that myself. And good paint about the high flow cat's.
    Reply With Quote  
     

  8. #8 Re: CAT or O2 Sensor 
    Donating Users Deezul_AwT's Avatar
    Join Date
    Feb 2008
    Location
    Cumming GA
    Posts
    2,156
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    Quote Originally Posted by Scimmia View Post
    Are you running a stock cat? If not, many aftermarket cats throw this code all of the time, they just don't work as well as OEM.
    I don't think that it's that they don't work as well. I thought it was that they worked "too" well, and the O2 Sensor wasn't seeing enough particles. I would think that it would be illegal to put on a cat that doesn't meet EPA standards, and I'm sure the car manufacturers wouldn't make their cats any more efficient than they needed to be. But I might be wrong.
    2016 Ford Fusion Energi Titanium - Still trying to figure out what I can do
    2006 Mercury Mariner Hybrid - K&N Drop in filter. Not much else you can do...
    TOTALED 9/2016 - 2004 Impala SS
    SOLD 3/2013 - 2000 Grand Prix GT
    Reply With Quote  
     

Similar Threads

  1. Iat sensor ?
    By GTP4 in forum PCM Tuning
    Replies: 9
    Last Post: 10-18-2008, 11:14 AM
  2. O2 sensor
    By 04 GTP COMP G in forum 3.8L V6 Supercharged (L67)(L32)
    Replies: 2
    Last Post: 08-11-2008, 04:01 PM
  3. Is it possible to run without an O2 sensor?
    By Andrew_99GTP in forum PCM Tuning
    Replies: 9
    Last Post: 06-19-2008, 11:45 AM
Tags for this Thread

View Tag Cloud

Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •