P0455 on a 2019 Ford F 150 Super Crew

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 Ford F 150 Super Crew

Ranked from 953 NHTSA owner complaints filed for this vehicle.

Sort by:

1
Cracked or ruptured EVAP/fuel line
High severity
The documented rupture of the metal line from the canister area to the fuel rail on this vehicle is large enough to produce a large-leak code, not just a small one.
Reported in 1 NHTSA complaint
Parts:fuel line
2
EVAP purge/vent valve failure
High severity
The valve failure that led to an imploded fuel tank on this vehicle indicates a seriously compromised EVAP seal, consistent with a large-leak fault.
Reported in 1 NHTSA complaint
Parts:purge valve EVAP vent valve
3
Loose or missing fuel cap
Low severity
A cap left off or badly worn is the classic large-leak trigger.
Common cause
Parts:fuel cap
4
Disconnected large EVAP hose/line
Medium severity
A hose popped off a fitting produces an easily-detected large leak.
Common cause
Parts:EVAP hose
5
Cracked charcoal canister housing
Medium severity
A significant crack creates a large unmetered leak path.
Common cause
Parts:charcoal canister
6
Corroded/perforated fuel filler neck
Medium severity
Rust-through on the filler neck creates an obvious large leak path.
Common cause
Parts:fuel filler neck

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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