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  1. #1

    Default Another Code! P0449

    Ok so our 07 Denali has been running just fine with no codes since the dealer replaced the Trans Internal Mode switch... until the CEL came on with a code of P0449. No other codes.. I understand its the Evap Control circuit stuck in an "open" state. The problem im having is that I dont have any visual reference to know what is in this circuit or where the components are located so i can start troubleshooting. Anyone have experience with this code and components?

  2. #2


    This problem is a circuit code. Very easy to troubleshoot with a scanner as you can operate the valve and watch the feedback to see what is and what isn't working. Without a scanner you are shooting in the dark. You can check for voltage and ohm check the solenoid. It's either a bad solenoid or a wiring problem between the solenoid and the PCM. A scanner makes this job a breeze and without it can be a real expensive experience.

    2004 SILVERADO 2500HD LS
    Pro Comp Leveling Kit
    285-75-16 Cooper ST All Terrains
    Pro Comp Programmer
    Bilstein Shocks
    Linux Bed Liner
    Tinted Windows

    Other rides:

    1967 Landcruiser <350 Chevy>
    1970 Camaro
    1990 Geo Metro Convertible
    2007 FJ Cruiser

  3. #3


    my light is on same code -i had to go to Springfield il. a 100 mile trip the dealer said it wouldn't hurt. i filled up with shell silver and drove 65 and got the best milage i ever got.
    17 mpg.

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