P0442 on a 2010 Chevrolet Impala

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 2010 Chevrolet Impala

Ranked from 441 NHTSA owner complaints filed for this vehicle.

Sort by:

1
Faulty fuel filler neck flap/seal that doesn't reseal after fueling
Medium severity
An owner describes the internal filler flap that should stay closed remaining open, letting air into the fuel/vapor system — a textbook small-EVAP-leak cause.
Reported in 1 NHTSA complaint
Parts:fuel filler neck
2
Damaged or leaking fuel line
High severity
An owner found fuel lines wet and dragging on the ground with fuel visibly being lost over time, a leak path that can register as an EVAP/fuel system leak.
Reported in 1 NHTSA complaint
Parts:fuel line
3
Fuel level/pressure sensor fault following a stall-after-refuel event
Low severity
A reported failure to restart after refueling from empty suggests a fuel delivery or level-sensing fault that can coincide with EVAP monitor failures.
Reported in 1 NHTSA complaint
4
Loose or worn gas cap
Low severity
The most common small-EVAP-leak cause on any vehicle.
Common cause
Parts:fuel cap
5
Cracked purge valve
Low severity
A purge valve that doesn't seal fully produces a small, steady leak detected by the EVAP monitor.
Common cause
Parts:purge valve
6
Charcoal canister crack
Low severity
A hairline crack in the canister housing is a common age-related small-leak source.
Common cause
Parts:charcoal canister

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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