P0455 on a 2016 Ford Edge

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 Edge

Ranked from 883 NHTSA owner complaints filed for this vehicle.

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1
Purge valve/solenoid stuck open, allowing a large unmetered air path
High severity
Owners describe repeatedly replacing the purge valve/solenoid with the fault recurring quickly, consistent with a valve that fails to seal and creates a large system leak.
Reported in 3 NHTSA complaints
Parts:purge valve
2
Cracked or disconnected EVAP/fuel line
High severity
A hole in the fuel line (fuel odor, repaired but recurring) and a separate fuel-line-connection leak show the fuel/vapor lines on this platform are prone to failures large enough to register as a gross leak.
Reported in 2 NHTSA complaints
Parts:fuel line evap hose
3
Missing, loose, or damaged gas cap
Medium severity
A missing/ill-fitting gas cap is the classic cause of a large EVAP leak; one complaint notes chasing a purge-system code while explicitly lacking a gas cap.
Reported in 1 NHTSA complaint
Parts:gas cap
4
Corroded/rust-damaged fuel tank
High severity
A referenced recall for a corroded gas tank on this model points to tank corrosion as a plausible source of a large vapor leak.
Reported in 1 NHTSA complaint
Parts:fuel tank
5
Cracked charcoal canister
Medium severity
A split or cracked canister shell creates a large, unrecoverable vapor leak that fails the EVAP monitor outright.
Common cause
Parts:charcoal canister
6
Corroded or rusted fuel filler neck
Medium severity
Rust-through at the filler neck is a common large-leak source on higher-mileage vehicles in salt/road-spray regions.
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