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P0455

P0455 on a 2016 Ford Explorer

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 Explorer

Ranked from 2,432 NHTSA owner complaints filed for this vehicle.

Sort by:
  1. 1

    EVAP purge/vent solenoid failure (repeat failures)

    High severity

    Two separate owners had EVAP-related components (described as 'evap throttle'/'evap pump') replaced multiple times for a recurring EVAP code, large enough to be flagged repeatedly.

    Reported in 2 NHTSA complaints
    Parts:EVAP purge valveEVAP vent valve
  2. 2

    Loose or damaged fuel filler neck/seal

    Medium severity

    Owners report a loose filler neck causing spillage and leaking at the filler door, both large-leak-sized fault points.

    Reported in 2 NHTSA complaints
    Parts:fuel filler neck
  3. 3

    Canister purge valve stuck open

    High severity

    An owner's purge valve was found stuck open, leaking strong fuel vapors into the cabin - a large, continuous leak path.

    Reported in 1 NHTSA complaint
    Parts:purge valve
  4. 4

    Fuel tank or fuel line leak

    High severity

    One owner discovered fuel pouring from the front of the vehicle, a leak large enough to fail the EVAP large-leak test outright.

    Reported in 1 NHTSA complaint
  5. 5

    Loose, missing, or faulty gas cap

    Low severity

    The classic large-leak trigger; check cap seating/seal first.

    Common cause
  6. 6

    Split or disconnected EVAP hose

    Medium severity

    A popped-off or split hose is a common large-leak source in the EVAP 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

1

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.

2

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.

3

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.

4

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.

5

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