P0420 2hrs after purchasing '07 Z71

Discussion in 'Engine & Drivetrain' started by MN 07 TAHOE Z71, Apr 16, 2018.

  1. MN 07 TAHOE Z71

    MN 07 TAHOE Z71 TYF Newbie

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    Recently purchased a 2007 Tahoe Z71, less than 2 hours after leaving the dealership the check engine light came on. Code is P0420, should I jump right into replacing the catalytic converter or is there something else I should be looking at first?
    I was told it could be from condensation, a loose gas cap or possibly a bad 02 sensor. I had the light cleared and it came on again about 4 days later.
     
  2. kbuskill

    kbuskill ***CAUTION*** I do my own stunts!

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    I would take it back to the dealer and make them fix it.... whatever "it" is.
     
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  3. MN 07 TAHOE Z71

    MN 07 TAHOE Z71 TYF Newbie

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    I immediately notified the dealership and asked if I could come into their service center to figure out what was going on. They told me that wasn't an option and that I'd be better off using my own mechanic because theirs are GM certified and $130 an hr. I'm obviously not pleased with this dealership, though I bought an as is vehicle from what I thought was a reputable Chevy Dealer I do feel screwed and given zero options for them to fix it. If it is something like an 02 sensor I will have this replaced at home, catlytic converter I would not. So just trying to figure out if it's worth starting with the smaller things and working up to that or if in most peoples experience this turns out the be a bad cat.
     
  4. Dcmaynor

    Dcmaynor Full Access Member

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    I would think most dealers offer a minimum 300 mile 48 hour exchange, or at least the ones I use do. Contact the BBB and then GM will get the dealership acting nice.
     
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  5. MN 07 TAHOE Z71

    MN 07 TAHOE Z71 TYF Newbie

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    I think I might give that at try, thank you for the advise. Used dealerships I've dealt with in the past have always been more than happy to help if a issue came up on my vehicles even if purchased as is. So, I was a bit shocked at their response when this happened less than 24hrs after purchasing.
     
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  6. swathdiver

    swathdiver Full Access Member

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    You can swap downstream O2 sensors to eliminate the possibility of a weak sensor. That code by itself almost always (99.9%) means that the cat is bad. I just replaced mine with the Magnaflow Y-pipe and then sold a scrap dealer the old ones to help offset the cost. Now if they would only pay me!

    Welcome aboard btw and post up some photos of that special Z71 when you can!
     
  7. MN 07 TAHOE Z71

    MN 07 TAHOE Z71 TYF Newbie

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    Thank you! :) I'm in Minnesota so its currently a big block of ice and snow, but I will definitely get some pictures up soon!
    I was on the blazer forum for years, as that was my first love! lol
    I finally got brave and stepped it up to the Tahoe, though its having some issues I LOVE THE TAHOE!!! Super excited to start making it my own. :)
     
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  8. jz57

    jz57 Full Access Member

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    That dealer must know the P0420 code and check engine light issue before they sold you Tahoe. They reset the code and turn off the check engine light befor you hand over money. After you left the dealer parking lot, they claimed "Sold as it is".
     
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  9. swathdiver

    swathdiver Full Access Member

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    You're welcome! Which Blazer, the big one or the little ones? Always wanted both at differing times but never had one.
     
  10. RED TAHOE LS

    RED TAHOE LS Full Access Member

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    Times two (2), they cleared the light to sell it, that's the way they operate.
    David g
    ....:)
     
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