P0455 Honda Civic
EVAP System Leak Detected (Gross Leak) · Powertrain Code · Medium · Repair: Easy
What is P0455?
A large leak has been detected in the EVAP system. Check gas cap first — if secure, look for disconnected or cracked EVAP hoses, a stuck-open purge valve, or a leaking charcoal canister.
When the Honda Civic triggers code P0455 (evap system leak detected (gross leak)), it typically points to an issue in the powertrain system. Below you'll find the most common causes, symptoms, and repair options specific to the Honda Civic.
This repair is rated easy, meaning basic tools, no lift needed.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your Honda Civic.
Common Causes on Honda Civic
- Gas cap missing or completely worn out
- EVAP canister vent shut valve stuck wide open
- Large EVAP vapor line crack or disconnection
- Fuel filler neck corrosion causing large leak
- EVAP purge control solenoid stuck open
Symptoms
- Check engine light illuminated
- Noticeable fuel smell near vehicle
- Gas cap warning light on dashboard
- Failed emissions test
- Fuel economy noticeably decreased
Notes for Honda Civic
Honda fuel filler neck corrosion is a known cause of large EVAP leaks on Civic and Accord, especially in rust-belt states.