What P0442 Means
The EVAP system, which captures fuel vapor from the tank instead of letting it escape into the air, has detected a small leak somewhere in the sealed system.
Common Causes
- Loose or damaged fuel cap (the single most common cause)
- Cracked EVAP hose
- Faulty purge valve or vent valve
- Small crack in the charcoal canister
Symptoms You Might Notice
- Usually no drivability symptoms at all
- Check engine light on
- Possible faint fuel smell in rare cases
What to Check First
- 1
Check the fuel cap first — make sure it's tightened properly and the seal isn't cracked, this fixes the majority of P0442 cases
- 2
Inspect visible EVAP hoses for cracks or disconnection
- 3
If the cap and hoses look fine, a smoke test at a repair shop will pinpoint the leak location
Frequently Asked Questions
My check engine light for P0442 came on right after I filled up my tank — why?
You likely didn't tighten the fuel cap fully after refueling. Tighten it until it clicks, then the code should clear itself after a few drive cycles.