P0442 — EVAP System Leak Detected (Small Leak)
Low severityWhat it means
The evaporative emissions system, which captures fuel vapours from the tank, has a small leak. Fuel vapour is escaping to the atmosphere instead of being stored and burned. The most common cause is simply a loose or worn fuel cap.
Common symptoms
- Usually only the check engine light
- Occasionally a faint fuel smell near the car
Likely causes
- Loose, damaged or worn fuel filler cap (most common)
- Cracked or aged EVAP hoses
- Faulty purge or vent valve
- Damaged charcoal canister or filler neck seal
What to check first
- Remove and retighten the fuel cap, inspect its seal, then clear the code and see if it returns
- Inspect EVAP hoses around the charcoal canister
- Test the purge and vent valves
- Have a smoke test done to locate small leaks
Can you keep driving?
Safe to drive. It is an emissions fault rather than a mechanical risk, but it will fail an emissions inspection.
Frequently asked questions
What is the most common cause of P0442?
The most likely cause is: Loose, damaged or worn fuel filler cap (most common). Several other faults can set P0442 as well, so confirm the real cause with live data and the checks above before replacing any parts.
Can I just clear P0442 and keep driving?
Clearing P0442 with an OBD2 scanner turns the warning light off, but if the underlying fault has not been repaired the code will usually come back within a few drive cycles. Fix the cause first, then clear the code to confirm the repair worked.
How serious is P0442?
P0442 is a low-severity code. It rarely affects how the car drives, but it is still worth fixing so the engine runs efficiently and passes an emissions test.
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