How much does it cost to fix P0442 on a Toyota?

Repair costs for P0442 on Toyota vehicles typically range from $20 to $350 depending on the underlying cause. The most common fix is: Loose, cross-threaded, or worn gas cap seal failing the small-leak EVAP test..

Toyota Check Engine Code

P0442 on Toyota

Evaporative Emission Control System Leak Detected (Small Leak)

Severity: low DIY difficulty: 1/5 Toyota cost: $20–$350

Last updated April 30, 2026 Also covers: Lexus, Scion

P0442 on Toyota: what makes it different

Toyota's EVAP system uses a tightly sealed network of hoses, a charcoal canister, and a vacuum switching valve to control fuel vapor recirculation. Because the system is designed to detect even small leaks, P0442 shows up frequently and is usually tied to something simple rather than a major failure.

Most-affected engines

2AZ-FE 2.4L (Camry, RAV4)
2GR-FE 3.5L V6 (Camry, Highlander)
1ZZ-FE/2ZZ-GE (Corolla, Matrix)
2AR-FE 2.5L (Camry, RAV4)

Common model years: 2005–2018

Most likely cause on Toyota

Loose, cross-threaded, or worn gas cap seal failing the small-leak EVAP test.

Known Toyota engine-family issues

Toyota EVAP lines run close to the undercarriage on several models, making them prone to cracking from age, heat cycling, and road salt exposure over 8–10+ years. The gas cap is by far the number one cause and should always be checked first.

Toyota-specific causes (most common first)

Gas cap not tightened to full click or worn O-ring seal
Cracked or brittle EVAP hoses near the charcoal canister (common as hoses age)
Charcoal canister vent valve stuck or clogged with debris
Small crack in the fuel tank filler neck or EVAP line from road debris/corrosion
Faulty purge valve not sealing fully at idle
Aftermarket fuel cap that doesn't match OEM sealing spec

Toyota-specific diagnostic tip

Before touching the EVAP hardware, replace or hand-tighten the gas cap and clear the code, then drive several cycles to see if it returns — Toyota's EVAP monitor runs only under specific temperature and fuel-level conditions, so it can take a day or two to re-trigger.

Symptoms drivers report

Check engine light
No drivability issues

Typical repair cost on Toyota

Most Toyota owners fix P0442 for between $20 and $350, depending on which underlying cause turns out to be at fault. Start with the most-likely cause for your vehicle — Loose, cross-threaded, or worn gas cap seal failing the small-leak EVAP test. — before throwing parts at it.

Toyota P0442 FAQ

Will P0442 cause my Toyota to fail emissions testing?

Yes, in most states an active EVAP code like P0442 will fail an OBD2 emissions check, so it's worth fixing before inspection time.

Is P0442 dangerous to drive with?

No, it's a vapor containment issue, not a drivability or safety issue — your Toyota will run fine, but fuel vapor may escape instead of being recirculated.

Why does the code keep coming back after I tighten the gas cap?

If tightening the cap doesn't resolve it after a few drive cycles, the leak is likely elsewhere in the EVAP hose routing or the canister, which needs a smoke test to pinpoint.