P0455 on a 2021 Ford Escape
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 2021 Ford Escape
Ranked from 326 NHTSA owner complaints filed for this vehicle.
- 1
Cracked fuel injector body leaking fuel/vapor (NHTSA recall 25S76 / 25V467)
High severitySame dominant recall pattern as this vehicle's small-leak code: cracked injectors leak fuel/vapor, producing persistent gasoline odor, fires, and EVAP-adjacent codes.
Reported in 20 NHTSA complaintsParts:fuel injector - 2
EVAP purge or vent solenoid failure
Medium severityTwo EVAP solenoids were replaced on one vehicle without resolving the fuel-vapor issue; another owner's purge valve fault stalls the engine on refueling.
Reported in 2 NHTSA complaints - 3
Fuel filler door/cap not sealing or latching
Low severityA fuel lid that will not close was directly reported to trigger the check-engine light.
Reported in 1 NHTSA complaint - 4
Gas cap loose, missing, or damaged (general)
Low severityRule out first on any large EVAP leak code.
Common causeParts:gas cap - 5
Cracked/split EVAP hose or line
Medium severityA bigger breach anywhere in the vapor system trips the large-leak threshold.
Common cause - 6
Rusted or damaged fuel filler neck
Low severityCorrosion at the neck-to-tank joint opens a large vapor path.
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.