DTC P0496: EVAP System - Flow During Non-Purge: Description
WARNING: This page is about a different car, the 2002 Suzuki XL-7. However, it is still accessible from the selected car via links, so may be relevant.
When engine is running, ECM closes EVAP canister vent valve and opens EVAP canister purge valve. If EVAP system is in good shape, EVAP control system pressure which was detected by fuel tank pressure sensor decreases. After which ECM closes EVAP canister purge valve leaving EVAP canister vent valve closed. If EVAP control system is in good condition, fuel tank pressure will then rise a specified rate.