P0455 Leak or Blockage Detected in Evaporative Emission Control System.
PCM monitors the EVAP system for no purge flow, and the presence of a large fuel vapor or several smaller ones.
The system fails when there is no purge flow ( attritubed to fuel vapor blockages or restictions), a large fuel vapor leak or several smaller ones by the EVAP running loss moniter test running, but not at idle.
Causes
-aftermarket EVAP hardware, such as fuel cap different from OEM
-disconnected or cracked EVAP canister tube, EVAP canister purge outlet, or return tube
-EVAP canister purge valve stuck closed
-damaged EVAP canister
- damaged/missing fuel cap, also cap not correctly installed
-loose fuel vapor hose/tube to EVAP components
-block restrictions in fuel vapor tube hoses
-fuel vapor control valve tube assembly or fuel vapor vent valve assmebly blocked
-canister vent soleniod stukc open
-mechanically inoperative fuel tank pressure sensor
hope that helps
