P0455 on a 2011 Ford Fusion Hybrid

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 2011 Ford Fusion Hybrid

Ranked from 2,869 NHTSA owner complaints filed for this vehicle.

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1
Cracked fuel tank at the top seam (purge-valve pressure-spike pattern)
High severity
A large cluster of owners on this exact vehicle report a cracked, actively leaking fuel tank matching the documented Ford recall tying tank cracking to canister purge valve pressure spikes - large enough to produce a big EVAP leak.
Reported in 8 NHTSA complaints
Parts:fuel tank
2
Failed or stuck-open canister purge valve
High severity
Multiple owners had the purge valve diagnosed as failed; a valve stuck open creates a continuous large leak path.
Reported in 5 NHTSA complaints
Parts:purge valve
3
Charcoal canister crack
Medium severity
Owners report vapor backing up into the fill tube and canister-linked fault codes consistent with a canister breach.
Reported in 3 NHTSA complaints
Parts:charcoal canister
4
Faulty capless fuel-fill inlet door/seal
Medium severity
A door that won't seal fully creates a persistent large-sized leak path at the filler.
Reported in 2 NHTSA complaints
5
Loose, missing, or faulty gas cap
Low severity
The classic large-leak trigger; check cap seating/seal before deeper diagnosis.
Common cause
6
Split or disconnected EVAP hose
Medium severity
A popped-off or split hose is a common large-leak source in this system.
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