P0442 on a 2020 Ford Explorer

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 Explorer

Ranked from 1,171 NHTSA owner complaints filed for this vehicle.

Sort by:

1
Purge valve malfunction (stuck open/closed)
Medium severity
Directly reported multiple times, including a documented P0496 evaporative purge-valve fault and a purge valve that wouldn't let the vehicle start after refueling — a failed purge valve breaks the EVAP system's ability to seal for leak testing.
Reported in 3 NHTSA complaints
Parts:purge valve
2
Fuel filler neck / capless fuel-fill valve malfunction
Medium severity
Owners report the fuel nozzle repeatedly clicking off and fuel spitting back during fill-ups, a classic sign of a sticking capless filler-neck valve that also compromises the EVAP seal.
Reported in 2 NHTSA complaints
Parts:fuel filler neck assembly
3
Loose or damaged gas cap/filler seal
Low severity
An incompletely seated or worn filler seal is the single most common real-world trigger for small EVAP leak codes.
Common cause
4
Cracked or aged EVAP vent/purge lines
Low severity
Heat-cycled rubber or plastic EVAP lines crack over time, opening a leak path in the system.
Common cause
5
Charcoal canister crack
Medium severity
Corrosion or impact damage to the canister housing creates a direct, often large, EVAP leak.
Common cause
Parts:charcoal canister
6
Rusted or corroded filler neck
Medium severity
Road-salt corrosion can perforate the filler neck over time, most common in northern climates.
Common cause
Parts:fuel filler neck

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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