P0455 on a 2019 Honda Accord Hybrid

P0455 means the EVAP system failed a leak check badly enough that the computer sees a large leak or no pressure/vacuum change.

Not your vehicle? See general P0455 info.

Most common causes on the 2019 Honda Accord Hybrid

Ranked from 529 NHTSA owner complaints filed for this vehicle.

Sort by:

1
EVAP canister vent valve stuck open or disconnected
Medium severity
One owner's vehicle threw a generic EVAP failure warning; a vent valve that won't close prevents the system from ever sealing for the leak test.
Reported in 1 NHTSA complaint
Parts:vent valve
2
Fuel filler door lock actuator fault preventing a proper seal
Low severity
A malfunctioning filler-door lock motor (reported on this VIN set) can keep the door from closing fully, allowing a larger, continuous leak path.
Reported in 1 NHTSA complaint
Parts:fuel filler door lock actuator
3
Loose, missing, or damaged gas cap
Low severity
A cap that won't seal is the classic large-leak trigger for this code; try a known-good cap before chasing anything else.
Common cause
Parts:gas cap
4
EVAP purge valve stuck open
Medium severity
A purge valve stuck open holds the system at atmospheric pressure and reads as a large, continuous leak.
Common cause
Parts:purge valve
5
Cracked or split EVAP hose/line
Medium severity
A larger split or a disconnected line produces the bigger leak rate this code is calibrated to detect.
Common cause
6
Charcoal canister crack or damage
Medium severity
Significant canister damage opens a large vapor path and commonly sets this code rather than the small-leak version.
Common cause
Parts:EVAP canister
7
Corroded or rotted fuel filler neck
Low severity
A perforated filler neck is large enough to fail the large-leak monitor outright.
Common cause

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These causes are aggregated from NHTSA owner complaints and general repair knowledge — this is not a diagnosis. P0455 on your car still needs shop confirmation before any repair.

Common symptoms

Check engine light
Fuel smell
Usually no performance issue
Failed emissions readiness

What to check before replacing parts

Check the gas cap first

Look for: A loose, missing, or cross-threaded cap is by far the most common cause of a large EVAP leak code — if it doesn't click to full tightness or the seal is cracked, that's very likely the whole fault.

Inspect visible EVAP hoses

Look for: A large leak is often obvious: a hose disconnected at a fitting, split open, or chewed through (rodent damage is common) rather than a hairline crack.

Command the purge and vent valves with a scan tool

Look for: A valve that doesn't respond at all when commanded open/closed, or stays open when it should seal, prevents the system from holding pressure/vacuum and reads as a large leak.

Smoke-test the system

Look for: With a large leak, expect an obvious plume of smoke or a clearly audible hiss at the fault location — it should be easy to spot compared to a small-leak diagnosis.

Inspect the canister and filler neck

Look for: A cracked charcoal canister housing or a corroded/rusted-through filler neck (common on older vehicles) can leak enough to prevent the system from ever holding vacuum.

Rather have a pro handle it? Find a vetted local mechanic.

Matching symptoms

Check Engine Light