Sorry guys. I thought the TCH pressurized the tank to reduce gasoline fumes. It doesn't.

I read the service manual. There is a pressure sensor that is used to make sure the system is airtight, but it doesn't appear to keep a positive pressure on the tank.

A charcoal filter is used to trap the fumes. The canister then feeds the fumes into the engine air intake to burn them off. Between "recycling" the fumes and keeping the system airtight, evaporative emissions are kept to "zero".

Sorry about my mistake.