Tracking P0455 on Your 2021 Hyundai Sonata
A P0455 on your 2021 Sonata indicates the ECM found a large EVAP leak. Your 8th-generation Sonata with the 2.5L or 1.6L turbo is within Hyundai's 5-year warranty. The gas cap is the first thing to check.
Evidence
- Check engine light with P0455
- Possible fuel odor
- Gas cap not clicking
- Emissions monitor incomplete
Causes Ranked
- Gas Cap Seal (Very High Likelihood): Loose or worn. Tighten or replace. Warranty-covered.
- Canister Close Valve (Medium Likelihood): Hyundai's vent valve. Warranty-covered.
- Purge Control Solenoid (Medium Likelihood): Stuck open. Warranty-covered.
- Vapor Line (Low Likelihood): Cracked. Warranty-covered.
- Charcoal Canister (Low Likelihood): Saturated. Warranty-covered.
What to Do
Tighten the gas cap and drive 2–3 days. If P0455 persists, visit a Hyundai dealer—all warranty-covered.
Warranty Coverage
Hyundai's 5-year/60,000-mile warranty runs through 2026. The federal emissions warranty (8yr/80k) covers EVAP through 2029.
Safe to Drive?
Yes. P0455 doesn't affect the Sonata's engine, 8-speed, or any features.