DTC P0456 Or DTC P1456: Description
WARNING: This page is about a different car, the 2002 Nissan Sentra. However, it is still accessible from the selected car via links, so may be relevant.
This diagnosis detects very small leaks in the EVAP purge line between the fuel tank and EVAP Canister Purge Volume Control Solenoid Valve (EVAP-CPVCSV) using engine intake manifold vacuum. If ECM detects a very small leak, DTC P0456 or P1456 will set. If ECM detects a small leak, DTC P0442 or P1442 will set.