What to check for a OBD II P0456 Code? I replaced the gas cap and no help! on 2007 Nissan Sentra

I have checked the ODB II codes and it displays P0456 which is a Evap. Emission Control System Small Leak. Gas cap has been replaced but do not know what to check next.


Asked by for the 2007 Nissan Sentra
use a smoke machine and watch for smoke exiting the system at any EVAP component. Any where there is smoke exiting the system, that is the faulty component. Do not pressurize the EVAP system with air pressure. Doing so can damage the purge and vent solenoids in the system.