Error code P0446 EVAP system vent control incorrect.
The Vapor Pressure Sensor VSV reads 0 ohms, so I assume it is wrong.
But
The charcoal canister doesn’t flow.
The question is if the VSV is bad will the Charcoal Canister still flow?
I am expecting air to flow from the purge port to the vent port (air cleaner side) with the other 2 external ports plugged.
The question is are both bad?
From what I remember of the vapor recovery system on Toyotas, the air flows from the vent to the purge outlet, i.e. the engine vacuum when applied to the purge port draws air through the canister from the vent. There would probably be a check valve to prevent pressure inside the canister from getting to the vent.
The VSV I believe stands for Vacuum Switch Valve. It is a solenoid operated switch that switches the Vapor Pressure Sensor from the tank side of the system to the canister side. The resistance should be in the 50 to 100 ohm range. If this solenoid were shorted, a fuse should be blown or an open collector transistor in the ECM will have openned.
Also there should be a VSV that blocks the flow vapors from the tank to the canister so the VPS can check that the vapor recovery plumbing is patent and gas tight. The VPS looks for pressusre in the tank when the canister flow is open and pressure rise when the canister flow is blocked.
Hope I have helped. Let us know what you find is the problem.
If this is the first time for this code, I would ignore it and stop overfilling the gas tank. Stop at the first click, period. If it doesn’t go away in two weeks, then do some troubleshooting.