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  1. #1

    Default error code P0446

    So last december this code popped up on my 2004 gmc sierra. turned out the EVAP vent solenoid was bad and it was replaced under my trucks warranty. My truck is out of warranty now and the same code popped back about a month ago. I called the dealership where i got it fixed and the solenoid was 1 year warranty so i brought it to the dealership for them to test it. They say the check engine light just turned off when i dropped it off (i think they cleared it and couldn't get the code to pop back up and didnt know what else to do) but they said they tested the solenoid and it was fine. so anyway i took it home and about a week later the code came back on.

    i did a search a found this:

    So could my problem be the vent is clogged? The EVAP solenoid is brand new and supposedly working fine. It said the problem is caused by dust getting in there. Sense i got it fixed last december the truck hasnt seem any dirt roads or dust. All highway driving. Could the heavy usage of salt they use up here clog up the vent?

  2. #2


    I would still say that since it is up again take it to them and show it is back on. since it is the same code for what was fixed should be done free.
    2004 Silverado 2500 Crew Cab 4x4, AMSOIL EA air filter, Granatelli MAF sensor, Throttle body spacer, Magnaflow exhaust (true dual to 2 in 1 out muffler), 6" ProComp lift (add a leaf and 5" superlift rear block), Bilstein shocks, 35's (Cooper Disoverer ST) and 4.10 gears, Rhino Liner, EGRUSA fender Flares and widow visors, extended stainless steel brake lines, firestone airbags w/onboard air compressor, Pioneer Avic X940BT navigation, Accel backup camera.
    1960 Land Rover Series II 88
    2001 Pontiac Sunfire
    2013 Toyota Avalon Limited (Wife's Car)
    NRA Life Member

  3. #3


    They said even though its the same code it would only be covered if the EVAP solenoid was defective sense thats all they replaced last time. They also said when i brought it back they tested the solenoid and it was working fine.

  4. #4

    Join Date
    Feb 2008
    Red Wing, Minnesota, United States


    Its most likely the vent on top of the tank, I had mine replaced under that same code and that took care of it. It was like $100 bucks total for my shop to drop the tank and rplace it.
    99 K1500 Suburban LT "THE BEAST"
    Hypertech III, K&N, true dual

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