DTC P0455: EVAP Control System Gross Leak Detected: Description
WARNING: This page is about a different car, the 2003 Infiniti G35. However, it is still accessible from the selected car via links, so may be relevant.
This diagnosis detects a very large leak (fuel cap fell off, etc.) in EVAP system between the fuel tank and EVAP canister purge volume control solenoid valve.