help cannot fix evap system code p1446

[scoobaru]

I'm tired of trying to fix this issue and not getting a solution. I need this working to get my registration renewed asap.
The car in question is a 2002 Legacy GT Wagon EJ25 w auto trans.

Update:
Replaced the drain valve $60 and did some testing and finally found the wiring pinouts.
Still not working but I'm going to try testing the wiring as I found paperwork stating it was repaired in 2008

[Rust2Runner]

Is this a stock setup?

[scoobaru]

yes
just replaced the plug and wires at the rear of the car just in case it was somehow still faulty
I can clear the code but it returns quickly

[Odycee]

Change gas cap?

[Boxer Wagon]

I work at an auto parts store. I'll run your code tomorrow and give you a list of reported fixes, plus I'll ask some of the mechanics that come in what their experience with it has been.

[Rust2Runner]

When you say 'changed drain valve', are you referring to the fuel tank pressure control valve? If that's been replaced then you likely have a bad wire. It's also possible to trip this code with a bad gas cap or cracked fuel filler tube apparently.

I see this code a lot... but it's normally on modified cars that have deleted the 2nd valve. They also usually have an aftermarket computer that can "ignore" the code. Since yours is stock, and I think of the year that only has the one valve (?), I'd check activity of the control wire to the tpcv. If that wire (the green/black one) is fine, I'd venture to say you have an open circuit in the tpcv.


edit: (you can also just toss a resistor on it and clear the code to trick the smog guy. I'm not versed in this enough to give it the official thumbs up for diy though)

[scoobaru]

already changed the gas cap with one that passed the test. I'll check the filler pipe for damage/rust next.
I doubt this will work with resistors as it has other sensors that see the pressure change from the vent valve closing.
I can't even flash my ecu with any of my tools I have a tactrix and vagcom

[prodriver1]

filler neck pipes rust really bad, the plastic cover for it holds dirt and salt forever, i pull the covers off all the subarus i work on and most are rusted and leaking. lots of people have had this problem and if you go to a junk yard and look i bet you will find at least one that is brand new. and its a super easy job.

[scoobaru]

ok filler neck is good has minor surface rust only
looks like the problem is electrical did some tests with the repaired wiring and its not getting even 1V.
wednesday I'm going to test the circuit from the ecu back and find the ground/power problem