P0455 on Hyundai
Evaporative Emission Control System Leak Detected (Gross Leak)
P0455 on Hyundai vehicles indicates evaporative emission control system leak detected (gross leak). Au7o has documented this code across 3 Hyundai models — most commonly on Accent, Elantra, Sonata. 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. Typical repair costs on Hyundai range from $20 to $450, depending on the specific model and root cause.
Common Causes of P0455
- •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
P0455 on Hyundai by Model
Hyundai Accent(1 issue)
- EVAP Canister Purge Control Solenoid Valve Sticking (P0441 / Stalling While Refueling)2006-2022
The canister purge control solenoid valve (PCSV) on the Accent sticks partially open or fails to hold vacuum, so fuel vapor flows into the intake at the wrong time. The classic owner pattern is a check engine light with P0441 (incorrect purge flow) plus the engine stalling or stumbling immediately after topping off at the pump, and a slightly rich, rough idle. Hyundai Forums threads on this go back years and turn up a second cause besides the valve itself: outdated ECM software, addressed by a Hyundai service campaign software update, which is sometimes the entire fix. The other frequently missed contributors are a saturated charcoal canister (from repeatedly overfilling the tank) and cracked purge lines.
Hyundai Elantra(1 issue)
- Evaporative Emissions Purge Valve and Fuel Tank Pressure Sensor Faults Triggering Check Engine Light2001-2006
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.
Hyundai Sonata(1 issue)
- P0455 — Gross EVAP Leak from Loose/Failed Gas Cap or Stuck Purge Valve2011-2019
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 Sonata/Sonata Hybrid EVAP system. Larger leaks can also come from a cracked EVAP/vent hose or a damaged charcoal canister.
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View P0455 across all makes →Frequently Asked Questions
What does P0455 mean on 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 specifically, this code is documented across 3 models.
What causes P0455 on Hyundai vehicles?▼
Common causes on Hyundai: 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. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0455 on a Hyundai?▼
Repair costs on Hyundai range from $20 to $450, depending on the specific model and root cause.
Which Hyundai models have P0455 documented?▼
Au7o has documented P0455 on 3 Hyundai models: Accent, Elantra, Sonata.