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  1. #1

    Default Help with code.....

    On the Suburban I have an intermittent "service engine light" which I understand to mean that there is an intermittent condition, that after it goes away will result in a number of "clean" starts (I think it's 5?) and then goes out. A few days later it will come back and so on and so forth....

    The code is a P0420 which the generic code reader defines as:

    "Catalyst System Below Efficiency Bank 1"

    Now what?

    2008 Suburban 1500 LT with all the goodies.
    2009 2500 Crew Cab DMax LT Stock under the hood.....Nerf bars, cap and liner, de-badged, Husky Liners, CB, JVC woofer, bull bar. Roof lights

  2. #2

    Default

    Quote Originally Posted by Oscarvan View Post
    On the Suburban I have an intermittent "service engine light" which I understand to mean that there is an intermittent condition, that after it goes away will result in a number of "clean" starts (I think it's 5?) and then goes out. A few days later it will come back and so on and so forth....

    The code is a P0420 which the generic code reader defines as:

    "Catalyst System Below Efficiency Bank 1"

    Now what?
    Could be a bad catalytic converter.

  3. #3

    Default

    Could be.....but I'm looking for a more systematic approach.

    2008 Suburban 1500 LT with all the goodies.
    2009 2500 Crew Cab DMax LT Stock under the hood.....Nerf bars, cap and liner, de-badged, Husky Liners, CB, JVC woofer, bull bar. Roof lights

  4. #4

    Default

    OK, ended up with a subscription to Alldata....

    Have to check the obvious but then it sounds indeed like the converter is toast.

    2008 Suburban 1500 LT with all the goodies.
    2009 2500 Crew Cab DMax LT Stock under the hood.....Nerf bars, cap and liner, de-badged, Husky Liners, CB, JVC woofer, bull bar. Roof lights

  5. #5

  6. #6

    Default

    Not yet.... The truck runs just fine, I have until next inspection (December lol).

    I think I will replace the O-2 sensors first..... (four of them). They get lazy anyways, and have 127 K on them.
    Then I suspect the Cat will have to be replaced. All in all about $600......

    I have no plans on selling this truck anytime soon.....I've had it since new, it's a part of the family.

    2008 Suburban 1500 LT with all the goodies.
    2009 2500 Crew Cab DMax LT Stock under the hood.....Nerf bars, cap and liner, de-badged, Husky Liners, CB, JVC woofer, bull bar. Roof lights

  7. #7

    Default

    One of the first things I did in the same situation (actually had a P0430, but the same idea) was to swap the two post cat sensors. If the code follows the sensor (meaning, if you start to get a P0430 instead of a P0420), then you have a good indication that the sensor/wiring is going bad. If the code remains the same, then it's probably not a problem with the sensors.
    '98 K1500 Suburban LS 5.7 L 4L60E NV246 ARB
    '92 Ford Explorer XLT 4x4 4.0 L A4LD BW13-54 Trac-loc rear
    "My toys were the greasy cogs and springs and pistons that lay around all over the place, and these, I can promise you, were far more fun to play with than most of the plastic rubbish children are given nowadays." Danny in Roald Dahl's Danny The Champion of the World

  8. #8

    Default

    I like it! Thanks.

    2008 Suburban 1500 LT with all the goodies.
    2009 2500 Crew Cab DMax LT Stock under the hood.....Nerf bars, cap and liner, de-badged, Husky Liners, CB, JVC woofer, bull bar. Roof lights

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