P0442 on a 2015 Toyota Corolla

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 2015 Toyota Corolla

Ranked from 218 NHTSA owner complaints filed for this vehicle.

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1
Charcoal canister crack or internal failure
High severity
Two owners had the EVAP charcoal canister replaced for a recurring check-engine light (one replaced it three separate times); Toyota issued canister-related service actions on this generation.
Reported in 2 NHTSA complaints
Parts:charcoal canister
2
Loose or improperly seated gas cap
Low severity
This owner's recurring check-engine light was repeatedly traced back to the gas cap not being fully seated, on top of an eventual canister fault.
Reported in 1 NHTSA complaint
Parts:fuel filler cap
3
Rodent-damaged fuel/EVAP line
Medium severity
One owner found rodent bite marks on a fuel line causing a leak on two separate occasions; rodent damage to vapor or fuel lines is a common real-world small-leak source, especially on cars that sit.
Reported in 1 NHTSA complaint
Parts:fuel line
4
EVAP purge valve stuck or leaking
Medium severity
A purge valve that fails to seal introduces a steady small vacuum leak the monitor detects.
Common cause
Parts:EVAP purge valve
5
EVAP vent valve failure
Medium severity
A vent valve that doesn't fully close allows outside air into the system during the leak test.
Common cause
Parts:EVAP vent valve
6
Cracked or deteriorated EVAP hose elsewhere in the system
Medium severity
Age-hardened rubber lines away from the fuel tank can also crack and leak vapor slowly.
Common cause
7
Corroded fuel filler neck
Low severity
Rust perforation at the filler neck creates a small but persistent leak path.
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.

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Matching symptoms

Check Engine Light