P0442
Low severityEvaporative Emission System Leak Detected (Small Leak)
Safe to drive. Like all EVAP leak codes, P0442 usually traces back to the gas cap. Tighten or replace it first.
What does the P0442 code mean?
The P0442 code means a small EVAP leak has been detected — bigger than what P0456 reports and smaller than P0455.
The EVAP system captures fuel vapors from your gas tank. When there’s a small leak, the most likely culprit is the gas cap, followed by EVAP hoses, valves, or the charcoal canister.
Can you keep driving with a P0442 code?
Yes. P0442 doesn’t affect engine performance. You’ll just lose a small amount of fuel as vapor and fail emissions inspections until it’s fixed.
What causes a P0442 code?
- Loose or worn gas cap~50%
- Cracked or loose EVAP hose~25%
- Faulty purge or vent valve~15%
- Cracked charcoal canister~10%
How to diagnose a P0442 (check these first)
- Tighten the gas cap firmly — it should click multiple times.
- Replace the gas cap if it’s old (over 5-7 years) or the seal looks worn.
- Visually inspect EVAP hoses for cracks or loose fittings.
- If the light returns after a new cap, a shop smoke-test finds the leak fast.
P0442 repair cost
Typical US ranges including parts and labor (varies by vehicle):
| New gas cap | $5 – $25 |
| EVAP hose replacement | $50 – $150 |
| Purge or vent valve | $80 – $200 |
Tools & parts that help
A new gas cap and a $20 scanner are usually all you need. The scanner clears the code so you don’t have to drive cycles waiting for it to reset.
See gas caps & OBD-II scanners ›P0442 — Frequently asked questions
Is it safe to drive with a P0442 code?
Yes. The engine runs normally; only fuel vapors are escaping in tiny amounts. Fix the gas cap and you’re done in most cases.
Will tightening the gas cap fix P0442?
Often yes. Tighten it until it clicks several times, drive a few cycles, and see if the light clears.
How much does it cost to fix a P0442?
Usually $5-$25 if it’s just a gas cap. More if it’s an EVAP hose or valve.
How long until the code clears?
After 2 to 5 complete drive cycles if the cause is fixed. Or use a scanner to clear it instantly.
Related codes
General guidance based on the standard definition of the P0442 code. A real diagnosis depends on your make, model, mileage and other symptoms. When in doubt, have a professional confirm the cause before replacing expensive parts.