P0455 on a 2019 Toyota Rav4

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 Toyota Rav4

Ranked from 869 NHTSA owner complaints filed for this vehicle.

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1
EVAP vent valve / fuel tank pressure control fault
Medium severity
Five owners on this exact model/year describe the fuel pump shutting off early or fuel gushing back at about half a tank -- a stuck vent valve or tank pressure sensor fault that prevents the system from venting/sealing correctly is consistent with a large EVAP leak result.
Reported in 5 NHTSA complaints
Parts:EVAP vent valve fuel tank pressure sensor
2
Cracked or leaking EVAP line
Medium severity
One owner reports a persistent and worsening gasoline smell on startup, consistent with a vapor leak large enough to be noticeable in the cabin.
Reported in 1 NHTSA complaint
Parts:EVAP hose
3
Cracked charcoal (EVAP) canister
Medium severity
A cracked canister housing leaks vapor directly and is a common age-related failure; look for fuel smell near the rear underbody.
Common cause
Parts:charcoal canister
4
Rusted or corroded fuel filler neck
Medium severity
Road salt corrodes the filler neck/pipe over years, opening a leak path that a new gas cap won't fix.
Common cause
Parts:fuel filler neck
5
Cracked or damaged fuel tank (large leak)
Medium severity
Corrosion, road debris impact, or a bad tank seam can open a large leak path that will consistently fail as P0455 rather than P0442.
Common cause
6
Loose, cracked, or missing gas cap
Low severity
The single most common source of a small EVAP leak; a cap that doesn't seal (or was left off after fueling) lets the system fail its leak-monitor test.
Common cause
Parts:fuel cap

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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