P0440 on Hyundai: How to Diagnose & Fix
Evaporative Emission Control System Malfunction
1 Hyundai model · 1 documented issue · $50-$300 repair
P0440 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…
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)
P0440 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 P0440 mean on a Hyundai?
P0440 stands for "Evaporative Emission Control System Malfunction." This code indicates a general malfunction in the Evaporative Emission Control (EVAP) system, which captures fuel vapors from the gas tank and routes them to be burned by the engine instead of escaping into the air. The computer ran a self-test and detected the sealed vapor system isn't holding pressure or vacuum correctly, often signaling a leak somewhere in the system. The most frequent and easiest cause is a loose or faulty gas cap. The car will run normally, but it will fail an emissions test and may smell faintly of fuel. On Hyundai it is documented across 1 model: Elantra.
What are the most common causes of P0440?
The most common causes of P0440 are: Loose, damaged, or missing gas cap, Cracked or disconnected EVAP hose, Faulty purge valve/solenoid, Faulty vent valve/solenoid, Leaking charcoal canister, Damaged fuel tank filler neck or seal, Faulty leak detection pump or pressure sensor. The specific cause varies by vehicle.
How much does it cost to fix P0440 on a Hyundai?
Published repair estimates on Hyundai range from $50 to $300 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 P0440 on a different make?
View P0440 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.