Fuel tank pressure sensor code is usually a couple of things. Could be as simple as the gas cap. Or it could be as simple as the charcoal canister valve or it's wiring and/or the valve switch. Or a bad plastic hose going to the canister or to the intake, check for cracked plastic hoses going to the canister. Most likely it's NOT the fuel pump if you can hear the pump whine when you turn the key to the ON position. You can check the evaporative canister switch by applying power to it and see if it clicks open and closed. The computer opens and closes the valve as you are driving down the road to clear out the charcoal of gasoline fumes. Then when it's parked as the tank get warm, the gasoline fumes expand and must vent somewhere...they go to the charcoal canister and are held there until you drive the car again, then the valve on the canister opens and engine vacuum sucks in the fumes and they are burned with the gasoline, then the charcoal tank is ready to accept and hold a fresh dose of gasoline vapors.
It is a sealed system to prevent gasoline fumes from evaporating into the atmosphere, gasoline fumes expand when going from cold at night, to warm during the day. (ever opened a 5 gallon gas can and WHOOSH!) If you open / remove your gas cap when it is hot out, and hear air/gas vapors rushing out of the gas cap, you have a defective system. Also don't over fill your tank with fuel, when the nozzle clicks off once at the gas pump, your done, leave it, don't keep trying to pump in another few cups by pulling the pump nozzle lever a bunch of times.
It's usually a cheap and easy fix... gas cap, or canister valve, valve wires, or plastic hoses bad, cracked, or incorrectly installed. The only pain is if it's the plastic tubing that goes from the top of the fuel tank up into the engine bay and charcoal canister. If that is cracked or broken, or was not installed correctly during a previous fuel pump installation, then you will have to drop the tank.
