OBD codes / P0455 / Honda Accord
P0455 on a Honda Accord
Evaporative Emission System Leak Detected (Large Leak)
All modern Accords with sealed EVAP.
What P0455 usually means on a Accord
P0455 flags a large evaporative-system leak on the Accord, most often from the gas cap or the canister vent valve. Fuel vapor is escaping instead of being routed to the engine to burn. It will not hurt driveability but will fail an emissions test. Honda's vent valves and aging EVAP hoses round out the usual causes.
Most likely causes on this model
- Loose or worn gas cap
The most common P0455 cause on Accords; check and re-seat the cap first.
- Canister vent valve stuck open
Honda vent valves stick, especially in salt-belt cars, preventing the system from sealing.
- Cracked EVAP hose
Aged lines near the tank and canister split and leak large vapor volumes.
- Damaged EVAP canister
A cracked charcoal canister leaks and sets large-leak faults.
What it costs on a Accord
A gas cap is a fifteen-to-thirty-dollar fix that clears many of these after a few drive cycles. The canister vent valve is a moderate, accessible part on most Accords. Only a full canister replacement approaches the higher end, and it is still a minor repair overall.
Year, engine and mileage change the answer. Get a diagnosis for your Accord — it weighs these causes against your exact configuration and real complaint data.
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Honda Accord problems & recalls by year
Based on widely reported patterns for this model; individual causes vary by year, engine and history. Generic P0455 behavior is covered on the main P0455 page. Confirm with a scan tool before buying parts.