P0442 on a 2017 Ford F 150 Crew Cab

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 2017 Ford F 150 Crew Cab

Ranked from 1,066 NHTSA owner complaints filed for this vehicle.

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1
Capless ('Easy Fuel') filler seal or inlet check-valve leak
High severity
This truck uses Ford's capless fuel filler; several owners report smelling fuel vapor near the filler with no overfill, and the fill flap/seal not sealing after refueling — a well-documented small-leak path on the capless system.
Reported in 2 NHTSA complaints
Parts:fuel filler seal capless filler check valve
2
Fuel tank pressure/venting fault during towing (TSB-documented stall)
Medium severity
A Ford technical service bulletin covers intermittent stalls on 2.7L-equipped trucks when coming to a stop while towing, tied to fuel tank venting/pressure; two complaints match this exact TSB.
Reported in 2 NHTSA complaints
3
Cracked or leaking fuel line/EVAP line
Medium severity
Two complaints describe a pressurized fuel line leaking at a steel-to-nylon transition fitting near the tank, a direct vapor/liquid leak path.
Reported in 2 NHTSA complaints
Parts:fuel line
4
Purge valve failure
Medium severity
A purge valve that leaks when it should seal lets in unmetered vapor/air and can trip a small-leak code; one owner suspected a 'valve solenoid' problem after stalling at fill-up.
Reported in 1 NHTSA complaint
Parts:purge valve
5
Vent valve (canister vent) failure
Low severity
A vent valve that won't seal prevents the EVAP system from holding pressure/vacuum during its self-test.
Common cause
Parts:vent valve
6
Cracked charcoal canister
Low severity
A physically cracked canister housing leaks vapor and will not pass the EVAP monitor's leak test.
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.

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Matching symptoms

Check Engine Light