Possible Causes
WARNING: This page is about a different car, the 2003 Nissan Pathfinder. However, it is still accessible from the selected car via links, so may be relevant.
ECM illuminates MIL and sets DTC P0456, when EVAP control system has a very small leak or does not operate properly. Possible causes are:
- Incorrect fuel tank vacuum relief valve.
- Incorrect fuel filler cap.
- Fuel filler cap remains open or fails to close.
- Foreign matter in fuel filler cap.
- Leak in hose between intake manifold and EVAP-CPVCSV.
- Foreign matter in EVAP Canister Vent Control Valve (EVAP-CVCV).
- Leak in EVAP canister or fuel tank.
- Leak or blockage in EVAP purge line.
- Leak or blockage in hose to EVAP Control System Pressure Sensor (EVAP-CSPS).
- Loose or disconnected hose.
- Defective EVAP-CVCV or circuit.
- Defective EVAP-CPVCSV or circuit.
- Defective fuel tank temperature sensor.
- Missing or damaged EVAP-CVCV "O" ring.
- Defective water separator.
- EVAP canister saturated with water.
- Defective EVAP-CSPS.
- Defective refueling control valve.
- Leak in On-Board Refueling Vapor Recovery (ORVR) system.
- Defective fuel level sensor or circuit.
- Foreign matter in EVAP-CPVCSV.