DTC P0455: Evaporative Emission (EVAP) Control System Leak Detected (No Purge Flow or Large Leak)

P0455 - EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM LEAK DETECTED (NO PURGE FLOW OR LARGE LEAK)

Description:	The powertrain control module (PCM) monitors the complete evaporative emission (EVAP) control system for no purge flow, the presence of a large fuel vapor leak, or multiple small fuel vapor leaks. System failure occurs when no purge flow, which is attributed to fuel vapor blockages or restrictions, a large fuel vapor leak, or multiple fuel vapor leaks are detected by the EVAP running loss monitor test with the engine running, but not at idle.
Possible Causes:	After market EVAP hardware (such as the fuel filler cap) non-conforming to required specifications Disconnected or cracked fuel EVAP canister tube, EVAP canister purge outlet tube, or EVAP return tube EVAP canister purge valve stuck closed Damaged EVAP canister Damaged or missing fuel filler cap Insufficient fuel filler cap installation Loose fuel vapor hose/tube connections to the EVAP system components Blockages or restrictions in the fuel vapor hoses/tubes (items also listed under disconnections or cracks) Fuel vapor control valve tube assembly or fuel vapor vent valve assembly blocked Canister vent (CV) solenoid stuck open Mechanically inoperative fuel tank pressure (FTP) sensor
Diagnostic Aids:	Check for audible vacuum noise or significant fuel odor in the engine compartment or near the EVAP canister and fuel tank.
Application	Key On Engine Off	Key On Engine Running	Continuous Memory
All	-	-	GO to HX: Evaporative Emission (EVAP) Monitor and System STEP HX47.