The fuel tank emission system has a small air leak. The Toyota dealer should have used their scan tool to troubleshoot and narrow down the problem areas. The issue may be a leak (crack) in the canister and a leak in one of the smaller plastic hoses, both can trip these codes. A leaking gas cap can also trip these codes but the dealer should have tested the cap.
If you want, Toyota may sell just the gas cap gasket or you can replace the complete cap. If the car has the same issue after replacement you can replace the canister yourself but the part is expensive. Shop around for aftermarket parts at places such as www.rockauto.com
or try a salvage yard to save money. Since you know the problem areas you could also have a non-Toyota shop do the work and save a few dollars. Again the parts are available for other sources then Toyota.
AutoZone will read trouble codes for free or your can buy a low cost code reader that plugs into the cars ODBII port.
This is an emissions issues, the car will still run OK. If your car requires smog inspection it may or may pass the test. Basically the fuel system is leaking gas fumes into the air instead of storing them in the canister and having the engine burn them. As such the car is no longer meeting environmental standards.
For more details download the Gen_4 Diagnostics Section from the link below.