P0446 Code i just dont understand

Discussion in 'GM Powertrain' started by Prophet1990, Jan 24, 2010.

  1. Prophet1990

    Prophet1990 Rockstar 100 Posts

    Hello, about 3 weeks ago a "sevice engine soon" light came on. Not a problem or so I thought, the code reads

    Trouble Codes Present:
    p0446: EVAP control System Vent Control Circuit

    Now Iv called about 4 diffrent places and even went to the dealer. All have told me something diffrent

    Iv tried a new gas cap thats not it. BUT iv heard it can be the charcoal canister(?) the Vent Valve(?) canister vent solenoid(?) Im so confused on how this setup is it seems like there could be 1,000,000 diffrent possibilities here... I dont understand how this is all hooked up either or how it works... if anyone has some input that can help me please reply. I have 0 knowledge on this due to everyone telling me something diffrent.

    Is it just one part but called diffrent names? or am i just lost...

    from my understanding the setup goes
    Gas tank>charcoal canister>canister vent solenoid>Vent valve then to the engine. Also Iv read

    "Turned out to be the purge solenoid on top of the intake manifold. I've seen a mechanic bud of mine squirt a little sea foam in the valve to free carbon that gums it up. He said it works about half the time. The other half just end up needing a new purge solenoid. Give it a try, worse case you buy a new solenoid the one you have isn't working anyway. [​IMG] "

    so how what the hell is this purge solenoid and how does it come into play here? i just need some clearifying on this and possibly some help full ideas on how to fix this problem so I can get it pass emissions and get my new plates on it... Thank you so much.

    -Sincerely Alex. :sign0011:
  2. azdrtdog

    azdrtdog Epic Member 5+ Years 100 Posts

    On my 99 it had a connection on the charcoal cannister find the 3/8 plastic line tha runs fom the motor to that. On the ends of that line is where you find the valves (kinda) the one on cannister is at elec.plug and the one at motor is same story
  3. vncj96

    vncj96 Epic Member 5+ Years 1000 Posts

    i just had the vent on top of the gas tank replaced and it fixed it. 150 bucks total for the shop to drop the tank and replace the vent
  4. Prophet1990

    Prophet1990 Rockstar 100 Posts

    hey all

    sorry for the delay, i read online the proper way to clear the code. it turned out it was my gas cap, I pulled the EBCM fuse and the EBC 1 fuse and it cleared the code right up, took it back for emissions, passed and got my new plates :) hopefully this could help someone later on! and save some $, if those are not the correct names of the fuses just let me know and I will get the correct ones but they are located in the fuse box under the hood not inside the cab the instructions are.

    1. start the truck
    2. pull the 2 fuses
    3. wait 5ish minutes
    4. turn the truck off
    5. put the fuses back in
    6. start the truck up, will start very hard and might not start at all the first 1-3 times, after its as good as gold.

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