P0455 on a 2018 Honda Cr V

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 2018 Honda Cr V

Ranked from 2,094 NHTSA owner complaints filed for this vehicle.

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1
Cracked or deteriorated EVAP line, hose, or fuel tank
Medium severity
One owner reported a persistent, unexplained strong gasoline odor the dealer could not pinpoint — consistent with a larger EVAP-side leak path such as a cracked line or tank seam.
Reported in 1 NHTSA complaint
Parts:EVAP hose
2
Purge valve stuck open
Medium severity
A dealer explicitly documented a 'purge flow malfunction' on one of these vehicles; a purge valve stuck open lets the EVAP system leak to atmosphere, which large-leak monitors will catch quickly.
Reported in 1 NHTSA complaint
Parts:purge valve
3
Gas cap not tightened, damaged, or missing
Low severity
The classic cause of a large/gross EVAP leak code; a cap left loose or with a worn seal is the first thing to rule out.
Common cause
Parts:gas cap
4
Charcoal canister crack
Low severity
A significant crack in the canister housing produces a large enough leak path to fail the EVAP monitor quickly.
Common cause
Parts:charcoal canister
5
EVAP vent valve stuck open
Low severity
A vent valve stuck open prevents the system from ever sealing, which is read by the monitor as a large leak.
Common cause
Parts:vent valve
6
Rusted or damaged fuel filler neck
Low severity
A significant corrosion hole or crack at the filler neck is large enough to set the large-leak code rather than the small-leak code.
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