Select year models of the Honda Civic Si may have problems with the EVAP canister vent solenoid. It stops responding to commands to open and close, and the following occurs:
The valve is located on the charcoal canister, and is meant to open and close upon command. It fails due to corrosion breaking one of two internal seals, which allows air to escape the system, signaling the OBD trouble code P1457.
Correcting the problem can be done by replacing the vent valve, or, in some cases, cleaning and resealing the vent valve has been successful. You can get an estimate for this repair here.
A worn, missing, or loose gas cap can cause the same issues.