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  1. #1

    Default 2001 silverado 5.3 p0446

    I keep getting a P0446 code on my truck and have been reding on the net and found this true.
    04-06-0055) for code P0446 on 2000-03 Cadillac, Chevrolet and GMC full size utility trucks. </P>The charcoal canister stores gasoline vapors from the tank. When certain driving conditions are met, the computer supplies power to the purge and vent solenoids. The purge solenoid opens the vacuum line between the canister and the intake manifold and engine vacuum sucks the vapors out of the charcoal. The vent solenoid opens a fresh air line into the canister.
    If these vehicles are driven in dusty conditions, road grit and dust can accumulate in the vent solenoid resulting in a restriction. That will set a P0446 code.
    The fix is to replace the vent solenoid and bracket with a newer design. Remove the old vent valve bracket and install the new bracket (part #15105605) and a new vent valve (part # 15750484). Then, clear the trouble code.
    </DIV>if so it might be my problem because I am on dirt roads all of the time.

  2. #2
    Jr. Engineer Rumpamuro's Avatar
    Join Date
    Apr 2007
    Mississauga, Ontario (Canada)


    i had this code problem before,

    this is what you gotta do, on some models your prefilter is located on the end of the tranny, if you drive in mud and dist like you say you do it will be clogged, so gms solution is to tell mechanics, relocate the prefilter forward and additional 8 5/8 inches (220 mm) from its current location, so now your gonna move your new prefilter and its gona line up where the bell housing ends, your prefilter starts, same level just move it forward.

    --> Rocco "Rumpamuro"

    --> Apprentice Mechanic (Cars and Trucks)

    --> Mississauga, Ontario (Canada) eh!

    --> Vehicles on the driveway:

    -2008 GMC Acadia SLE AWD

    -2007 Silverado Classic Reg cab, long box.

    -2008 Pontiac Vibe (my dads fuel efficient way to go to work)

    -1996 Pontiac Sunfire GT

  3. #3


    I do not see a pre filter is it on the top between the transmition and the body?
    I see the break stuff and I see the fulr lines but not the filter.
    I do see a hose that comes down across the top of the transmition and stops on top of the cros beam that the transmition is mounted to

  4. #4
    Jr. Engineer Rumpamuro's Avatar
    Join Date
    Apr 2007
    Mississauga, Ontario (Canada)


    If you cannot find this prefilter than the first tsb hasnt been done, sorry i forgot to mention this i figured 01 in dusty areas youd have this problem once already, but anyways there is a tsb so im not sure if the dealer would still cover it, the tsb is for 99-07.

    this is what has to be done anyways

    First go to the dealer and if they wont do it they should supply you with the kit, part # 19152345

    -Locate your canister vent valve electrical conector (sorta in the corner of the bed (drivers front corner, underneath) and disconnect it, some models dont have this.

    -unclip the two clips holding it to the underbody and throw em out.

    -disconect the vavle vent pipe at the evap canister
    -take out the bolt, make sure you keep this
    -take out the evap canister vent valve with the bracket and throw it out
    -bolt up the new valve assembly to the underbody with the bolt and hole from before.
    -connect the vent valve pipe to the evap canister
    -install the vent valve pipe clips into the existing hjoles in the underbody
    -plug in the electrical connector(if there is one)
    -attach 5/8 heater hose to the vent valve port and run it in the frame rail up to the top area of the tranny.
    -install the new prefilter box, make sure you install it where i posted previosuly not where the kit tell you to.
    -attach the prefilter box with some zip ties to the fuel lines, make sure the filter box opening is pointing down.
    -dont forget to tie wrap your hose you put in the frame rail.

    Good luck.

  5. #5


    thankyou for your help.
    as soon as the dealer parts department opens on monday I will go get the part and do the install. It sounds pretty simple.
    I have one more question. In the mean time will just clearing the code and driving the truck be ok?

  6. #6
    Jr. Engineer Rumpamuro's Avatar
    Join Date
    Apr 2007
    Mississauga, Ontario (Canada)


    Id say yes, we had a truck with this code, 03 silverado, it was skyservices pick up truck, we didnt even know that code existed with our snap on scanner till i put the tech 2 gm scanner on it and god knows how long it was driving for with the code.
    Last edited by Rumpamuro; 07-19-2008 at 10:33 AM. Reason: sp

  7. #7
    Join Date
    Mar 2010
    Grand Haven, Michigan

    Default Retired

    I also have found the p0446 code by chance. But the question I would ask pertains to the 6.0 liter,, 8 cylinder to 4 cylinder engine. I have notice recently that when the engine is operating in the 4 cylinder mode I get a noise like a chatter and goes away when back to 8 cylinder. Could that be the solenoid trying to operate but not??? I will be taking the truck in for the code tomorrow,, but the noise "drives me nuts"! (It is different than normal 4 cylinder mode operation noise and vibration).

  8. #8


    I have the same code (0446) on my 2001 silverado. I have replaced the solinoid valve and the vent valve kit. The SES light is still on. Should this go out on its own or should I clear the fault code with my scanner? Any help would be great. Thanks.

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