P0442 on a 2017 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 2017 Ford Explorer

Ranked from 1,669 NHTSA owner complaints filed for this vehicle.

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1
Purge valve failure/sticking
Medium severity
One owner had the purge valve replaced as part of a documented EVAP repair; another reports the fuel-vapor purge valve sticking and causing RPM flares -- both are classic small-leak/monitor-fault triggers.
Reported in 2 NHTSA complaints
Parts:purge valve
2
Charcoal canister and EVAP sensor degradation
Medium severity
Same owner's shop replaced EVAP-related sensors and the charcoal canister/tubing while chasing a persistent post-refuel stumble, indicating multiple worn EVAP components.
Reported in 1 NHTSA complaint
Parts:charcoal canister
3
Cracked fuel-tank sending-unit/fuel-pump gasket leaking gasoline near the tank top
High severity
Dealer-confirmed cracked gasket at the sending unit/fuel pump on top of the tank, right next to the exhaust -- a large-enough leak that it was treated as a fire-safety repair.
Reported in 1 NHTSA complaint
Parts:fuel tank fuel pump
4
Damaged or pinched fuel line
High severity
An intake hose clamp installed in the wrong position rubbed through the metal fuel line, causing raw fuel to leak onto the engine and vapors to enter the cabin.
Reported in 1 NHTSA complaint
Parts:fuel line
5
Fuel filler cap/neck not sealing correctly during refueling
Low severity
Owner reports fuel spilling out every time the tank reaches full, suggesting a filler-neck/cap venting problem.
Reported in 1 NHTSA complaint
6
Loose or damaged fuel filler cap (general)
Low severity
The single most common P0442 trigger industry-wide; verify the cap seals and clicks fully before chasing anything else.
Common cause
7
Cracked or perforated EVAP hose
Medium severity
Age- or heat-cracked vapor lines are a common small-leak source not otherwise called out in this batch.
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.

Rather have a pro handle it? Find a vetted local mechanic.

Matching symptoms

Check Engine Light