P0446 code for GMC Canyon Vent solenoid valve. Evap canister, charcoal canister. Emission.

How to problem solve a P0446 code on GMC Canyon. Evap canister, charcoal canister, gas vapor cannister, for GMC Canyon.
Clogged evap emissions canister. Evap vent solenoid control.
If you have a OBD 2 scanner that is able to do a fairly simple evap pressure test, what it will do is command the vent solenoid to close, when the ignition is turned off. The test is done when the engine is off. I had my scanner hooked into the port, and I had the door open, and the cord to the scanner outside of the truck door when I push the button and initiated the test. I listened closely, and I could hear the flap of the vent solenoid closing. I Just confirmed that the electrical wiring was proper and that the solenoid was being commanded closed.
The OBD 2 scanner that I used was the Seekone OBD 2 scanner. For the price and it’s features it seems this one is one of the best on the market. I ordered it online and it was delivered to my home. It does live engine data, and as I said it will do an Evap test and command the solenoid to close. The only thing that I really wish this scanner could do is give me misfire count data for each cylinder, which it does not do. I do highly recommend the scanner for the features and functionality and its price.
Do you have a Scanner yet? If you just have one that is just a cheap one, and will not show you the live data of the engine specifications when it is turned on and running (live feedback data) such as the fuel trims and thermostat temperature etc, then I believe it would be a useful upgrade to get a decent Scanner. The Seekone scanner also is able to do a battery test and also tells you if the alternator is working properly. Shows you live battery voltage. Anyways, if you get this scanner for future vehicle analysis, then essentially you can use it for free to do the Evap test which it is capable of doing, so for free. When I used the scanner to do the test, all I was doing was starting the test and listening to hear if the "click" noise of the vent valve closing could be heard. The truck engine is off, so it is fairly easy to hear, if the vent solenoid operates properly to close the vent. If you hear the vent closing, then you have confirmed that the electrical wiring to the solenoid and within the solenoid are working properly. If you hear no "click" of the vent closing, as I am guessing that you will hear no "click" because likely your vent solenoid valve could be broken, then you will have confirmed that that is what is causing your gasoline to back up the filler neck and over spill. A vent valve that is faulty could be stuck in the closed position while the engine is off, and this would cause the refueling problem. The vent valve is normally open when the engine is off.
If a vent valve is already closed down tightly against the seat, then you would hear no "click" of the valve closing because it is already closed. If you hear no "click" then you know it is either a faulty vent solenoid valve, to be replaced, or it is faulty wiring leading to the connection of the vent solenoid valve. If your vent valve is seized in the open position, it will set a P0455 code.
Did you use compressed air to blow through the Canister to try and clear out any dust? If you leave the tube connected that leads from the canister to the vent solenoid, and blow the compressed air through the inlet hole (the 'nipple') that usually connects the line from the gas tank, and use your finger to block the 'nipple' that usually connects the line that runs to the purge valve, then the compressed air will go straight to the vent valve container, where there may be some dust in the filter there..
Then you can reverse this procedure and block the nipple from the gas tank, and blow air through the purge valve nipple, and try to get more dust out.
Actually, better advice would be to leave the line from the canister to the vent valve solenoid DISCONNECTED, when you start out the whole blowing air technique. This way any dust you get out of the canister will exit from the nipple that usually connects to the line leading to the vent, thus not blowing any more dust than necessary through the vent valve and filter. Then once the canister itself is fully cleaned out, then you can connect the line to the vent valve, and concentrate on then cleaning out the line leading to the vent valve and the filter below the vent valve.
I wanted to give an update that replacing the fuel tank pressure sensor on this GMC Canyon did fix the P0446 code!
I personally feel that the two main parts to fix this particular code would be 1) the Vent Valve solenoid or wiring, and dust 2) the Fuel Tank Pressure Sensor or wiring.
I would NOT personally replace the Purge Valve solenoid for this code. Purge would set a different code.
If you are having problems filling gasoline into the gas tank, it has nothing to do with the Purge Valve. I personally had 2 problems with MY truck's Evap system 1) a clogged canister and vent system 2) a faulty FTP sensor