DTC P0456: - Evaporative Emission System Leak Detected (Very Small Leak)

WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2009 Mercury Mountaineer, 2009 Mercury Milan, 2009 Mercury Mariner, 2009 Mercury Grand Marquis, and 2009 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.

DTC P0456: - EVAPORATIVE EMISSION SYSTEM LEAK DETECTED (VERY SMALL LEAK)

Description:	The powertrain control module (PCM) monitors the complete evaporative emission (EVAP) control system for the presence of a very small fuel vapor leak. The system failure occurs when a fuel vapor leak from an opening as small as 0.508 mm (0.020 inch) is detected by the EVAP running loss monitor test.
Possible Causes:	Very small holes or cuts in the fuel vapor hoses/tubes Loose fuel vapor hose/tube connections to the EVAP system components EVAP system component seals leaking. See the Possible Causes for DTC P0442
Diagnostic Aids:	Check for a missing fuel filler cap or the integrity of the cap. Verify the capless fuel tank filler pipe is sealed correctly (if equipped). Check for loose or damaged vapor hoses. Visually inspect the EVAP canister inlet port, CV solenoid filter, and canister vent hose assembly for contamination or debris.
Application	Key On Engine Off	Key On Engine Running	Continuous Memory
All	-	-	GO to Pinpoint Test HX .