P0442 on Hyundai: How to Diagnose & Fix
Evaporative Emission Control System Leak Detected (Small Leak)
2 Hyundai models · 2 documented issues · $20-$400 repair
P0442 on Hyundai by model: symptoms, diagnosis and fix
On the Sonata, P0442 (small EVAP leak, ~0.020-0.060 in) most often comes from a simple sealing failure or the Natural Vacuum Leak Detection (NVLD) assembly. The gas cap O-ring hardens/cracks with age, and rust on the filler-neck sealing surface prevents a good seal. Hyundai has acknowledged (TSB 21-01-035H) that salt/marine environments contaminate the NVLD sensor, and Sonata Hybrid (2011-2015) is specifically prone to NVLD-driven small-leak codes in coastal areas. A canister purge valve that seals poorly can also produce a small leak.
Common Symptoms
- Check engine light (no drivability change)
- Occasional faint fuel odor
- Failed emissions readiness monitor
How to Fix
Start with the cheap items: inspect/replace the gas cap and clean the filler-neck sealing surface with a Scotch-Brite pad. Smoke-test the EVAP system to locate the leak. Replace the NVLD assembly if contaminated/faulty (Hyundai has issued an updated EVAP air-filter kit and NVLD replacement guidance for salt-contaminated units), and replace a leaking purge valve.
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, tether or sealing interface is confirmed defective Fitment/availability: Hyundai 31010-3L600, cataloged for 2007-2023 Sonata and 2011-2019 Sonata Hybrid. Confirm VIN and inspect the filler neck; a new…
- Genuine Hyundai canister purge valveOEMHyundai 28910-25100
purge valve after bidirectional command/isolation testing confirms leakage when closed Fitment/availability: Hyundai 28910-25100 for cataloged 2005-2014 Sonata applications; use here only for 2011-2014 non-hybrid branch after VIN/origina…
- Genuine Hyundai canister purge valveOEMHyundai 28910-3C200
purge valve after bidirectional command/isolation testing confirms leakage when closed Fitment/availability: Hyundai 28910-3C200 for cataloged 2015-2019 Sonata GDI/TCI-GDI applications. Confirm VIN and engine; hybrid fitment is not infer…
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Sources for this issue (3)
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…
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
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)
P0442 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 P0442 mean on a Hyundai?
P0442 stands for "Evaporative Emission Control System Leak Detected (Small Leak)." This emissions code means the evaporative emission (EVAP) control system has detected a small leak. The EVAP system seals the fuel tank and captures gasoline vapors, routing them to be burned in the engine instead of escaping into the air, and the computer periodically pressure- or vacuum-tests the system to confirm it's sealed. A small leak the size of about a 0.040-inch hole will set this code. By far the most common and cheapest cause is a loose, damaged, or missing gas cap, so that's the first thing to check, though any cracked hose or worn seal in the system can also trigger it. On Hyundai it is documented across 2 models: Sonata, Elantra.
What are the most common causes of P0442?
The most common causes of P0442 are: Loose, damaged, or missing fuel filler cap, Worn or cracked gas cap seal, Cracked or disconnected EVAP hose or line, Faulty purge valve or vent valve, Damaged O-ring or seal at the fuel tank or filler neck, Small crack in the charcoal canister, Leaking fuel tank sending unit gasket. The specific cause varies by vehicle.
How much does it cost to fix P0442 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.
Looking for P0442 on a different make?
View P0442 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.