P0455 on Hyundai: How to Diagnose & Fix
Evaporative Emission Control System Leak Detected (Gross Leak)
2 Hyundai models · 2 documented issues · $20-$400 repair
P0455 on Hyundai by model: symptoms, diagnosis and fix
A common recurring complaint on XD-generation Elantras is an illuminated check engine light caused by EVAP system faults, especially purge control valve issues, loose or aging gas caps, and fuel tank pressure sensor problems. Owners often notice no drivability problem, but the car repeatedly fails emissions inspection. These faults are widely discussed in owner forums and repair databases for early-2000s Elantras.
Common Symptoms
- check engine light
- failed emissions inspection
- fuel smell near engine bay or rear of car
- intermittent rough idle after refueling
How to Fix
Smoke-test the EVAP system, inspect the gas cap seal, and command the purge valve on and off with a scan tool to verify operation. Replace the faulty purge solenoid, damaged hoses, or pressure sensor as needed, then clear codes and complete an EVAP drive cycle. Avoid replacing parts blindly without leak testing because multiple small leaks can set similar codes.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Hyundai 28910-22040 purge control valveOEMHyundai 28910-22040
purge-solenoid replacement only after command/vacuum testing confirms the purge branch Fitment/availability: 2001-2006 Elantra within the retailer's 1995-2006 fitment; replaces 28910-22030. Confirm gasoline engine, VIN and connector.
- Genuine Hyundai 31010-2C700 fuel-filler capOEMHyundai 31010-2C700
fuel-cap replacement only when seal/ratchet/pressure-vacuum inspection confirms the cap branch Fitment/availability: 2001-2006 Elantra within the retailer's 2000-2006 fitment; replaces 31010-2D600.
- Genuine Hyundai 31435-1EA00 fuel-tank pressure sensorOEMHyundai 31435-1EA00
tank-pressure sensor replacement only after scan/signal response testing confirms the sensor branch Fitment/availability: 2001-2006 Elantra within the retailer's 2000-2006 fitment; replaces 31435-2D501 and 31435-38100. Confirm VIN and in…
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Owner tips & cautions
- TipStart with the gas cap and a visual hose inspection before replacing sensors, since cracked EVAP hoses and worn cap seals are common on older Elantras.
- TipUse a smoke test if the code returns after replacing the purge valve; small leaks are easy to miss by eye.
Sources for this issue (1)
P0455 (large/gross EVAP leak, ~0.040 in or larger) on the Sonata is most commonly a loose, missing, or failed gas cap, a canister purge valve stuck open (constant EVAP vacuum leak), or a faulty NVLD sensor — the same coastal salt-contamination pattern Hyundai has documented (TSB 21-01-035H) affecting the 2011-2015 Sonata Hybrid EVAP system. Larger leaks can also come from a cracked EVAP/vent hose or a damaged charcoal canister.
Common Symptoms
- Check engine light
- Strong fuel/gasoline odor near vehicle
- Failed emissions readiness
- Sometimes rough idle if purge valve stuck open
How to Fix
Verify the gas cap is tight and its O-ring is intact; replace if degraded. Smoke-test to find the gross leak. Replace a stuck-open canister purge valve or a cracked EVAP line; replace the NVLD assembly if contaminated. Re-run the EVAP monitor to confirm the leak is sealed.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Hyundai fuel-filler cap assemblyOEMHyundai 31010-3L600
fuel-cap replacement after its seal or retention is confirmed defective Fitment/availability: Hyundai 31010-3L600, cataloged for 2007-2023 Sonata and 2011-2019 Sonata Hybrid. Confirm VIN and inspect the neck; it is not a universal cure f…
- Genuine Hyundai canister purge valveOEMHyundai 28910-25100
purge valve after command/isolation testing confirms it remains open Fitment/availability: Hyundai 28910-25100 for cataloged 2005-2014 Sonata applications; use here only for 2011-2014 non-hybrid branch after VIN/original-number confirmat…
- Genuine Hyundai canister purge valveOEMHyundai 28910-3C200
purge valve after command/isolation testing confirms it remains open Fitment/availability: Hyundai 28910-3C200 for cataloged 2015-2019 Sonata GDI/TCI-GDI applications. Confirm VIN and engine; hybrid fitment is not inferred.
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Sources for this issue (3)
P0455 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0455 mean on a Hyundai?
P0455 stands for "Evaporative Emission Control System Leak Detected (Gross Leak)." This code means your car's evaporative emission (EVAP) system has detected a large (gross) leak, so fuel vapors that should be sealed inside the fuel and vapor system are escaping into the atmosphere. The EVAP system captures gasoline vapors from the tank and routes them to the engine to be burned instead of polluting the air, and the computer periodically pressure- or vacuum-tests this sealed system. A gross leak almost always points to something obvious and easy, like a loose, missing, or bad gas cap, rather than a deep mechanical failure. It rarely affects how the car drives, but it should be fixed to pass emissions and stop wasting fuel vapor. On Hyundai it is documented across 2 models: Elantra, Sonata.
What are the most common causes of P0455?
The most common causes of P0455 are: Loose, missing, or improperly tightened gas cap, Worn, cracked, or failed gas cap seal, Cracked or disconnected EVAP/vapor hose, Damaged or missing fuel filler neck seal, Faulty EVAP purge valve stuck open, Failed EVAP vent valve, Cracked or damaged charcoal canister. The specific cause varies by vehicle.
How much does it cost to fix P0455 on a Hyundai?
Published repair estimates on Hyundai range from $20 to $400 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.