P0442 on a 2018 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 2018 Ford Explorer

Ranked from 713 NHTSA owner complaints filed for this vehicle.

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1
Fuel tank / EVAP system leak (recall-related fuel vapor intrusion)
High severity
Numerous owners report a strong raw-fuel odor inside the cabin, with several directly citing Safety Recall 18S35 (fuel system EVAP leak) or a purge valve replacement; a raw-fuel smell indicates vapor escaping the EVAP system, which is exactly what sets a small-leak P0442.
Reported in 7 NHTSA complaints
Parts:fuel tank EVAP hose/line fuel filler neck
2
Purge valve (canister purge solenoid) failure
Medium severity
One owner reports the purge valve was replaced and the throttle body subsequently stuck closed, confirming an EVAP purge-side component was already faulted on this vehicle.
Reported in 1 NHTSA complaint
Parts:purge valve
3
Loose, worn, or improperly seated gas cap
Low severity
Standard first-check for any small EVAP leak code; a cap that won't seal fully allows vapor to escape and sets P0442.
Common cause
Parts:gas cap
4
Cracked or perished EVAP hose/line
Medium severity
Rubber EVAP lines harden and crack with age/heat cycling, producing a small vapor leak the EVAP monitor detects as P0442.
Common cause
Parts:EVAP hose
5
Charcoal (EVAP) canister crack
Medium severity
A cracked canister housing leaks vapor and is a common small-leak source on this platform.
Common cause
Parts:EVAP canister
6
Rusted or corroded fuel filler neck
Medium severity
Corrosion perforates the filler neck over time, creating a small vapor leak path.
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.

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Matching symptoms

Check Engine Light