P0442 on a 2019 Ford F 150 Supercab

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 2019 Ford F 150 Supercab

Ranked from 953 NHTSA owner complaints filed for this vehicle.

Sort by:

1
Purge valve malfunction (stuck closed) causing excess EVAP system vacuum
High severity
An owner's fuel tank purge valve issue caused idling/performance problems and the tank was later found imploded from vacuum - direct evidence the purge valve/EVAP control on this vehicle can fail and compromise the system's seal integrity.
Reported in 1 NHTSA complaint
Parts:purge valve
2
Cracked or ruptured fuel line near the canister/fuel rail
High severity
A metal fuel line from the canister area to the high-pressure fuel rail cracked and ruptured on this exact truck, a direct small-leak path in the fuel/vapor system.
Reported in 1 NHTSA complaint
Parts:fuel line
3
Loose or damaged gas cap
Low severity
An improperly sealed gas cap is the most common source of a small EVAP leak.
Common cause
Parts:gas cap
4
Cracked charcoal canister
Medium severity
A hairline crack in the canister shell produces a small, persistent vapor leak.
Common cause
Parts:charcoal canister
5
Faulty fuel tank pressure (FTP) sensor
Low severity
A drifting FTP sensor can report a leak signature even with an intact EVAP system.
Common cause
Parts:fuel tank pressure sensor
6
Cracked or brittle EVAP hose
Medium severity
Age-hardened EVAP hoses crack and leak small amounts of vapor over time.
Common cause
Parts: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