P0442 on a 2020 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 2020 Ford F 150 Super Crew

Ranked from 506 NHTSA owner complaints filed for this vehicle.

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1
Fuel line chafing near the tank creating a small seep
High severity
One owner found a fuel hose from the top of the tank had dropped and worn a hole against the frame; even a small weep here fails the small-leak monitor.
Reported in 1 NHTSA complaint
Parts:fuel line fuel hose
2
Capless filler neck flapper not sealing fully
Medium severity
A worn or sticky Easy Fuel flapper seal lets a small amount of vapor escape; suspect this with a persistent faint gas smell and no other leak found.
Reported in 1 NHTSA complaint
Parts:fuel filler neck
3
Fuel tank seam or fitting seep
Medium severity
The same underbody exposure that let a driveshaft puncture this platform's tank in one case shows the tank/fittings are exposed; a lesser impact can leave a smaller seep.
Reported in 1 NHTSA complaint
Parts:fuel tank
4
Loose or worn fuel filler cap
Low severity
The most common small-leak trigger; a cap that doesn't seal fully still passes casual inspection but fails the tighter small-leak monitor.
Common cause
Parts:fuel filler cap
5
Cracked or leaking EVAP purge valve
Low severity
A purge valve with a small internal crack lets vapor bleed past it even when closed, failing the small-leak test.
Common cause
Parts:purge valve
6
Faulty canister vent valve (small seal failure)
Low severity
A vent valve seat that's slightly worn allows a small, steady leak sensitive enough to trip the P0442 threshold.
Common cause
Parts:vent valve
7
Cracked charcoal canister or EVAP line
Medium severity
Age and road-salt exposure crack the canister housing or its connecting hoses just enough to fail the small-leak monitor.
Common cause
Parts:charcoal canister EVAP hose

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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