P0455 on a 2019 Kia Sorento

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 Kia Sorento

Ranked from 418 NHTSA owner complaints filed for this vehicle.

Sort by:

1
Low-pressure fuel pump seal leak (2018-2019 Kia fuel pump recall/warranty extension)
High severity
Kia's own recall/warranty-extension notice for a low-pressure fuel pump leak on 2018-2019 models matches this vehicle's repeated complaints of strong fuel smell and confirmed leaking pumps, large enough to fail the big-leak EVAP monitor.
Reported in 6 NHTSA complaints
Parts:fuel pump
2
Cracked EVAP line near the fuel tank
Medium severity
One owner was told directly by a mechanic that the leak was in the evaporative line above the tank, a direct large-leak EVAP source on this vehicle.
Reported in 1 NHTSA complaint
Parts:EVAP line
3
Loose or missing gas cap
Low severity
The single most common large-leak cause across all vehicles; recheck for a proper click and inspect the seal.
Common cause
Parts:fuel cap
4
Purge valve stuck open
Medium severity
A purge valve stuck open bleeds down system pressure rapidly, presenting as a large leak.
Common cause
Parts:purge valve
5
Canister vent valve failure
Medium severity
A vent valve that fails to close allows continuous atmospheric venting, a common large-leak trigger.
Common cause
Parts:vent valve
6
Charcoal canister crack
Medium severity
A significant crack in the canister housing can leak enough fuel vapor to fail the large-leak test.
Common cause
Parts:charcoal canister

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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