P0442 on a 2018 Ford F 150 Super Crew

P0442 means the EVAP system could not hold pressure or vacuum during a leak test, but the leak is small.

Not your vehicle? See general P0442 info.

Most common causes on the 2018 Ford F 150 Super Crew

Ranked from 1,835 NHTSA owner complaints filed for this vehicle.

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1
Capless fuel filler door/seal failure
Medium severity
A documented design flaw on this generation of F-150's capless fuel fill: the filler door's hinge spring wears and the swivel pin walks out of place, so the door no longer seals against weather/vapor, a common cause of small EVAP leaks.
Reported in 1 NHTSA complaint
Parts:fuel filler door seal
2
Cracked or leaking fuel vapor line
Medium severity
A persistent gasoline smell in the cabin after driving, only partially resolved by a dealer repair, is consistent with an intermittent EVAP/fuel vapor line leak.
Reported in 1 NHTSA complaint
Parts:EVAP hose
3
Purge valve stuck open or leaking
Medium severity
A leaking purge solenoid lets outside air into the system during the leak-detection test; command and verify operation with a scan tool.
Common cause
Parts:purge valve
4
Vent valve/solenoid failure
Medium severity
A stuck-open vent valve prevents the system from holding pressure/vacuum during self-test; bench or scan-tool test the solenoid.
Common cause
Parts:EVAP vent valve
5
Cracked charcoal canister
Medium severity
A physically cracked or corroded canister housing leaks vapor, usually found via smoke test.
Common cause
Parts:charcoal canister
6
Rusted or damaged filler neck
Low severity
Corrosion from road salt/moisture perforates the filler neck, especially on trucks with high underbody exposure.
Common cause

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These causes are aggregated from NHTSA owner complaints and general repair knowledge — this is not a diagnosis. P0442 on your car still needs shop confirmation before any repair.

Common symptoms

Check engine light
Fuel smell near vehicle
Usually drives normally
Hard start after fueling in some cases

What to check before replacing parts

Tighten and inspect the gas cap

Look for: A cap that doesn't click to full tightness, has a visibly cracked or flattened seal, or is simply missing is the single most common cause of a small EVAP leak — rule it out first.

Smoke-test the EVAP system

Look for: Because this is a small leak, expect only a thin wisp of smoke or a faint hiss at one spot (a hose, seam, or valve) rather than an obvious cloud — look closely and take your time.

Check purge valve sealing

Look for: A purge valve that doesn't hold vacuum when commanded closed lets a small amount of air bleed through, which the system reads as a leak during its self-test.

Inspect hoses near the tank and engine bay

Look for: Look for small cracks, soft/collapsed spots, or a hose that has pulled loose slightly at a fitting — any of these can leak just enough to trip a small-leak code without an obvious fuel smell.

Verify vent valve operation

Look for: A vent valve that doesn't seal fully when commanded closed prevents the system from holding vacuum during its self-test, which reads as a small leak even with no physical leak in the hoses.

Rather have a pro handle it? Find a vetted local mechanic.

Matching symptoms

Check Engine Light