1998 Subaru Impreza • 150,000 miles

I am having trouble figuring out what is causing DTC P0446: evap emission control system vent circuit malfunction, on my 98 Impreza L. Have hooked up a scan tool and cleared codes numerous times but check engine light would come back on within 10 seconds of starting the engine. I need to get this car inspected and am doing all of the work myself to fix it, and have very little money to spend, as I am a senior in high school. So I need to be 100% sure on what I need to check and/or replace to get rid of this code for good, or at least for until it passes inspection. I think it could be the canister vent solenoid, but I don't want to buy one just to find out it didn't fix it.
February 11, 2013.

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