P0442 on a 2019 Subaru Ascent

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 Subaru Ascent

Ranked from 433 NHTSA owner complaints filed for this vehicle.

Sort by:

1
Undiagnosed small EVAP/fuel-system leak causing persistent gasoline odor in cabin/garage
Medium severity
A cluster of owners independently report a strong raw-fuel or chemical smell entering the cabin at idle or after parking — the hallmark of a small EVAP leak — even though dealers repeatedly could not reproduce it.
Reported in 6 NHTSA complaints
2
Cracked/leaking EVAP fuel vapor canister
Medium severity
A dealer directly diagnosed a leak in the fuel vapor canister after the owner reported abnormal cabin fuel odor; the leak recurred even after the canister was repaired.
Reported in 1 NHTSA complaint
Parts:EVAP canister
3
Purge valve (canister purge solenoid) leaking
Medium severity
A purge valve that doesn't seal fully lets vapor bleed when it shouldn't, tripping a small-leak code.
Common cause
Parts:purge valve
4
Cracked or perished EVAP hose/line
Low severity
Age-hardened lines are a common small-leak source as the vehicle ages.
Common cause
Parts:EVAP hose
5
Loose, worn, or improperly seated gas cap
Low severity
Always the first, simplest thing to check/reseat before deeper EVAP diagnosis.
Common cause
Parts:gas cap
6
Rusted or corroded fuel filler neck
Low severity
Corrosion perforation of the filler neck is a common small-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.

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

Matching symptoms

Check Engine Light