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Thread: DTC codes even when turned off??

  1. #1

    DTC codes even when turned off??

    I have done several swaps but this one is strange...
    2010 L96 engine P38 ECM standalone with TH400 transmission. Fires right up and idles fine.

    I am getting P0442 and P0451 even when they are both set to "No error reported" - I have never experienced this before. Wiring for EVAP is removed completely.
    Hopefully someone will have an idea ??

    I am also getting P2122, P2127 and P2138 but those are of course not turned off so I have to troubleshoot the APP or maybe that they can be connected to the evap codes because of some ground issue?? Internal in the ECM maybe?

  2. #2
    Tuning Addict 5FDP's Avatar
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    May 2012
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    If they say permanent after the code, they will not go away when settings them to no error reported. They might go away on their own after tons of drive cylces but they may not.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
    Strange. I would think that any codes, even permanent ones would go away after a reflash... I have disconnected the battery from the vehicle overnight so I will take a look and troubleshoot some more when I get home.

  4. #4
    Senior Tuner mbray01's Avatar
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    Dec 2013
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    nope, permanent codes will never leave, until the code criteria is satisfied.Its new emissions standards that prevent guys with code readers from clearing codes, forcing drive cycles and getting around emissions tests. It has helped for me in the past to leave the box checked, but turn code to no error reported. It will eventually satisfy itself, and clear, but usually takes a long time.
    Michael Bray
    Rusty Knuckle Garage
    Slidell, Louisiana
    20yr Master Tech.
    Advanced Level Specialist
    Custom Car Fabrication, Customization, High Performance.
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  5. #5
    Advanced Tuner
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    That's the whole point of a permanent code. It's permanent. The acceptable conditions absolutely must be met before it will go away.