P0455 on a 2016 Ford Fusion

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 2016 Ford Fusion

Ranked from 1,659 NHTSA owner complaints filed for this vehicle.

Sort by:

1
Canister purge valve/solenoid failure
High severity
Multiple owners report the purge valve repeatedly failing on this vehicle, throwing check engine lights and causing rough running/stalling, sometimes needing repeat replacement.
Reported in 7 NHTSA complaints
Parts:purge valve
2
EVAP vent/blocking valve failure
Medium severity
One owner reports an EVAP blocking/vent valve failing and putting the vehicle into limp mode, matching a large, sudden EVAP leak path.
Reported in 1 NHTSA complaint
Parts:EVAP vent valve
3
Loose, worn, or missing gas cap
Low severity
This is the classic trigger for a large-leak EVAP code; confirm the cap seats and seals before further diagnosis.
Common cause
Parts:gas cap
4
Cracked or disconnected EVAP hose/line
Medium severity
A fully detached or split hose produces a large, continuous leak that a smoke test will find quickly.
Common cause
5
Cracked charcoal canister
Medium severity
A cracked canister housing vents vapor straight to atmosphere and fails the leak-detection test outright.
Common cause
Parts:charcoal canister
6
Rusted or corroded fuel filler neck
Medium severity
Advanced rust-through at the filler neck creates a large leak path, more common on higher-mileage, salt-belt vehicles.
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