What P0455 means for your Hyundai Elantra
P0455 means your Elantra's evaporative emissions (EVAP) system detected a gross (large) leak. The system pressurizes the fuel tank and vapor lines, then watches for a pressure drop. A drop bigger than 0.040 inches of vacuum loss triggers P0455. Hyundai Elantra P0455 is most often a failed canister vent valve or a worn fuel cap. The code is emissions-only and will not affect drivability, but most U.S. states will fail your inspection until it is fixed.
🎯 Top Causes on the Hyundai Elantra
🚗 Most Affected Elantra Model Years
| Year | Engine | Primary Cause | Typical Mileage | Notes |
|---|---|---|---|---|
| 2011-2016 | 1.8L Nu | CCV + cap | 60k-130k | CCV is the leading cause |
| 2017-2020 | 2.0L Nu MPI | Cap + canister | 40k-100k | Newer EVAP, fewer CCV issues |
| 2017-2023 | 1.6L turbo | Purge valve | 30k-80k | Turbo engines stress purge valve |
| 2021-2023 | 2.0L Smartstream | Fuel cap | 20k-50k | New design, cap-dominant failures |
🔧 How to Diagnose P0455 on a Hyundai Elantra
- Tighten the gas cap to three clicks and drive 2-3 complete cycles to allow the EVAP monitor to clear.
- Inspect the canister close valve under the car. Tap it lightly - sometimes that frees a stuck valve.
- Look at the charcoal canister for cracks or fuel smell near the rear axle.
- Smoke-test if the visual inspection finds nothing.
❓ Hyundai Elantra P0455 FAQ
Is Hyundai Elantra P0455 covered under any recall?
Not specifically as of late 2025. Check NHTSA.gov for your VIN as Hyundai has issued multiple recalls. Some powertrain warranty extensions on Theta engines may overlap.
How much to fix P0455 on a Hyundai Elantra?
$0-$30 for a fuel cap, $150-$300 for a CCV with labor, $300-$500 for a full canister replacement. Most P0455 fixes on Elantras stay under $200.
Why does my Elantra throw P0455 only after refueling?
Classic sign of a fuel cap that did not click on properly. Hyundai EVAP monitors run shortly after refueling and detect any pressure loss. Tighten harder next time.
Can I pass emissions inspection with P0455 on an Elantra?
No. P0455 will fail any OBD-II emissions test. The code must be cleared and the EVAP readiness monitor set before retesting.