P0442 on Toyota — EVAP system leak (small leak)
TOYOTA
2 sources
- Official data (NHTSA)official_feed
- Editorial sourceeditorial
What P0442 means
P0442 means the evaporative-emissions (EVAP) system has a small leak that lets fuel vapor escape. On Toyota vehicles the single most common cause is a loose or worn fuel cap; cracked EVAP hoses and a faulty purge or vent valve are the next suspects.
Driveability assessment not yet available. Get a personalized AI Second Opinion for your exact car.
General information, not a diagnosis or repair instruction. Always confirm with a qualified mechanic for your specific vehicle.
Common causes
- Cracked EVAP system hose
- Cracked or disconnected EVAP hose
- Faulty purge or vent valve
- Loose or worn fuel cap
- Loose or faulty fuel cap
Symptoms
- Occasional fuel odor
- Check-engine light with no drivability change
Frequently asked questions
Will tightening the gas cap clear P0442?
Often, yes — if a loose cap set the code, re-tightening it until it clicks and driving through a few warm-up/cool-down cycles will let the monitor re-run and clear the light on its own. If it returns, the cap seal, an EVAP hose, or a valve is leaking and needs a smoke test.