P0442 on a 2018 Chevrolet Traverse

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 Chevrolet Traverse

Ranked from 452 NHTSA owner complaints filed for this vehicle.

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1
Failed or stuck canister purge valve/solenoid
High severity
Repeatedly diagnosed and replaced in this batch (including a valve that failed the fix twice); this vehicle's known 'Valor' canister purge solenoid issue is a recurring EVAP fault.
Reported in 3 NHTSA complaints
Parts:purge valve purge solenoid
2
EVAP non-purge flow malfunction (companion P0496)
Medium severity
Two complaints report an explicit P0496 (EVAP flow during non-purge) alongside driveability symptoms, pointing to a purge/vent flow-path problem in the same system.
Reported in 2 NHTSA complaints
3
Capless fuel filler flap/seal wear
Medium severity
This Traverse's capless filler design is called out in this batch as a leak-prone point; a worn flap seal opens an unmetered air path into the EVAP system.
Reported in 1 NHTSA complaint
Parts:fuel filler neck seal
4
Cracked or leaking EVAP line/hose
Medium severity
A complaint of fuel odor detected in the cabin with no warning lights is consistent with a small EVAP line leak.
Reported in 1 NHTSA complaint
Parts:EVAP hose
5
Charcoal canister crack
Low severity
A cracked canister housing is a common small-leak source, especially with road-salt exposure.
Common cause
Parts:charcoal canister
6
EVAP vent valve stuck open
Low severity
A vent valve that doesn't seal allows a small, steady leak the system flags during its leak-check routine.
Common cause
Parts:vent valve

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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