P0302 on Hyundai: How to Diagnose & Fix
Cylinder 2 Misfire Detected
8 Hyundai models · 11 documented issues · 6 critical · $120-$8,000 repair
P0302 on Hyundai by model: symptoms, diagnosis and fix
The Theta II engine can seize due to metal debris blocking oil flow to connecting rod bearings. Hyundai issued recalls and extended warranties. Affected engines may need replacement.
Common Symptoms
- Knocking noise from engine
- Engine stalling
- Check engine light
- Loss of power
- Engine seizure
How to Fix
Check VIN for active recalls - Hyundai provides free engine replacement for affected vehicles. Install the knock sensor detection system (KSDS) software update that monitors for bearing wear. Change oil every 5,000 miles. If engine fails and under warranty, replacement is free. Out of warranty replacement: $4,000-8,000.
Owner tips & cautions
- TipDIY repairs can save significantly - dealer charges $4,000-8,000 but DIY costs are typically 50-70% less
- WarningThis is a high-severity issue - ignoring it can lead to costly repairs or safety concerns. Address it promptly.
- TipGet a proper diagnosis before replacing parts - similar symptoms can have different causes
Sources for this issue (1)
- NHTSA Recall 17V-224recall
The Theta II GDI engine in 2011-2019 Tucson models is susceptible to connecting rod bearing failure caused by manufacturing debris restricting oil flow. This can lead to catastrophic engine seizure, often without warning. Hyundai issued multiple recalls (19V-601, 20V-150) and extended the engine warranty to 15 years/unlimited miles for original owners.
Common Symptoms
- Metallic knocking from engine
- Engine stalling without warning
- Check engine light with P1326 code
- Loss of power while driving
- Excessive oil consumption
How to Fix
Check VIN for active recalls at NHTSA.gov. Ensure the Knock Sensor Detection System (KSDS) software update has been installed - this monitors for early signs of bearing failure and can put the engine in limp mode. If engine has seized, Hyundai will replace it under recall. Out-of-warranty replacement runs $4,500-7,500. Use full synthetic 0W-20 oil and change every 5,000 miles.
Find a Hyundai dealer
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Owner tips & cautions
- TipGet the KSDS software update immediately if not already done - it can detect bearing failure early and prevent catastrophic seizure
- WarningIf you hear any knocking noise, stop driving immediately. Continued driving can destroy the engine beyond repair
Sources for this issue (1)
The 1.8L Nu engine in 2011-2016 Elantras is prone to premature failure due to manufacturing defects including piston ring issues, connecting rod bearing failure, and oil passage problems. Metal debris from failed components can circulate through the engine causing catastrophic damage. A class action settlement covered these vehicles with extended warranty up to 140,000 miles.
Common Symptoms
- Engine knocking or ticking noise that increases with RPM
- Excessive oil consumption
- Check engine light illumination
- Oil pressure warning light
- Engine stalling or loss of power
- Metal shavings in oil
How to Fix
Check for coverage under the Nu Engine Settlement. Contact Hyundai dealer for software update (KSDS knock sensor detection system). Complete engine replacement if bearing failure has occurred. Regular oil changes every 3,000-5,000 miles to minimize sludge buildup.
Owner tips & cautions
- TipRegular oil changes every 3,000-5,000 miles to minimize sludge buildup.
- WarningThis is a high-severity issue - ignoring it can lead to costly repairs or safety concerns. Address it promptly.
- TipGet a proper diagnosis before replacing parts - similar symptoms can have different causes
Sources for this issue (4)
- ClassAction.org: New Hyundai, Kia Engine Failure Settlement Covers 2.1M Additional Vehiclesmedia
- MyCarVoice: Hyundai Elantra 1.8L Nu Engine Class Action Settlementmedia
- Sauder Schelkopf: Hyundai Elantra and Kia Forte Nu Engine Failures Class Action Investigationmedia
- Top Class Actions: Kia, Hyundai engine failure class action settlementmedia
Certain 2019-2020 Elantra sedans built with the 2.0L Nu MPI (Atkinson-cycle) engine were assembled with piston oil rings whose nitride heat treatment was inconsistent, leaving the rings excessively hard. The hardened outer periphery of the oil ring chips, and the chipped material scuffs the cylinder bore. The failure progresses in a recognizable order: first rising oil consumption between changes, then a deep metallic knock under load, then bearing damage and finally seizure and stall in traffic. Because the oil ring is the control ring, owners often see oil level fall a quart or more per 1,000 miles well before any noise appears. This is a manufacturing/heat-treat defect confined to specific engine build ranges on the 2.0L Nu MPI - it is not the same failure as the Nu connecting-rod bearing knock, and it does not apply to the 1.6L Gamma T-GDI Sport or the 1.8L Nu.
Common Symptoms
- Oil level dropping a quart or more between changes with no visible leak
- Low-oil warning light between services
- Metallic knocking or rod-knock sound that rises with engine speed
- Blue smoke from the exhaust on start-up or under load
- Engine stalls and will not restart
- Check engine light with misfire codes
How to Fix
Free recall remedy. Under NHTSA campaign 21V301000 (Hyundai campaign 203) dealers inspect the engine and replace it free of charge if scuffing or abnormal noise is found, and flash the Piston Noise Sensing System (PNSS) software that listens via the knock sensor and warns the driver before catastrophic failure. Owners who paid out of pocket for an engine before the campaign can seek reimbursement. Do not accept a 'consumption test only' answer without the PNSS software also being installed - the software is the early-warning half of the remedy. Keep every oil-change record; Hyundai has denied engine claims where service history could not be produced.
Sources for this issue (4)
- NHTSA Recall 21V301000 - Hyundai Recall 203, Improperly Heat-Treated Piston Oil Rings (2020 Elantra)recall
- 2019-2020 Hyundai Elantra Nu 2.0L Atkinson Engine Inspection (Recall 203)tsb
- Recall for 2019/2020 Elantras - Hyundai Forumsforum
- Hyundai Elantra, Kona and Veloster Recalled Due to Engine Problems - Consumer Reportsarticle
The Elantra Sport's 1.6L Gamma T-GDI is a direct-injection-only engine: no fuel ever washes across the back of the intake valves, so oil vapour drawn in through the PCV system bakes onto the valve stems and seats. Owners on the Elantra Sport community report visible deposits by roughly 60,000-90,000 miles, and heavier deposits on cars driven mostly short-trip. The deposits disrupt airflow and swirl, producing a shaky cold idle, hesitation off boost, cylinder-specific misfires and a slow erosion of power and fuel economy that owners often mistake for normal ageing. Turbocharging worsens it because higher blow-by loads the PCV system with more oil mist. This is specific to the direct-injected 1.6T - the port-injected 1.8L and 2.0L Nu MPI engines sold in the same bodies wash their intake valves with fuel and do not accumulate deposits this way.
Common Symptoms
- Rough or shaky idle when cold
- Hesitation or stumble under light throttle
- Cylinder-specific misfire codes
- Gradual loss of power and fuel economy
- Long crank on a cold start
How to Fix
Confirm by borescoping the intake ports through a removed intake manifold rather than guessing from symptoms. The only durable fix is mechanical cleaning - walnut-shell blasting of the intake ports and valve backs, typically repeated every 50,000-70,000 miles; chemical intake cleaners and fuel additives cannot reach the intake valves on a DI-only engine. Preventively, owners fit an oil catch can on the PCV side, keep oil-change intervals near 5,000 miles with a quality low-volatility oil, and avoid long strings of short cold trips. No recall or Hyundai campaign covers carbon cleaning; it is a maintenance item on this engine.
Sources for this issue (3)
The 2.0L Beta engine in this generation commonly develops valve cover gasket leaks as the rubber hardens with age and heat. Owners report oil seepage down the cylinder head, burning-oil smell, and in some cases oil collecting in spark plug wells that contributes to misfires. This is a well-known age-related issue in owner forums and repair databases for the XD Elantra.
Common Symptoms
- burning oil smell
- oil on top of engine
- oil in spark plug wells
- intermittent misfire
- light smoke from engine bay after driving
How to Fix
Inspect around the valve cover perimeter and inside the spark plug tube wells for fresh oil. Replace the valve cover gasket set, including spark plug tube seals if included, and clean the mating surfaces carefully. If oil has contaminated ignition components, replace spark plugs and any damaged wires or coils as needed.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- MAHLE Original VS50409 valve-cover gasket setOEMMAHLE VS50409
valve-cover reseal after inspection confirms the twelve-bolt Beta-engine cover branch Fitment/availability: Hyundai Elantra 2.0L with twelve-bolt valve cover from November 2002 through 2006. Confirm build date a
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (1)
P0302 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 P0302 mean on a Hyundai?
P0302 stands for "Cylinder 2 Misfire Detected." This code means the engine computer has detected a misfire specifically in cylinder 2, meaning that cylinder isn't completing combustion properly on some firing events. The computer watches tiny variations in crankshaft speed to spot when a cylinder fails to fire, and a misfire means the air-fuel mixture isn't igniting correctly — usually from a spark, fuel, or compression problem in that cylinder. You may feel a stumble, rough idle, shaking, loss of power, or a flashing check-engine light, and persistent misfires can damage the catalytic converter. Because it names a single cylinder, the fault is often a component serving just cylinder 2, like its coil, plug, or injector. On Hyundai it is documented across 8 models: Sonata, Tucson, Elantra, Genesis, Veloster, Genesis Coupe, Santa Fe, Accent.
What are the most common causes of P0302?
The most common causes of P0302 are: Worn or fouled spark plug (cylinder 2), Failed ignition coil or coil-on-plug (cylinder 2), Clogged or faulty fuel injector (cylinder 2), Vacuum or intake air leak affecting that cylinder, Low compression (worn rings, burnt/bent valve, head gasket), Damaged spark plug wire or boot (if equipped), Carbon-tracked or cracked coil/plug causing spark loss, Faulty PCM/ECM driver (rare). The specific cause varies by vehicle.
How much does it cost to fix P0302 on a Hyundai?
Published repair estimates on Hyundai range from $120 to $8,000 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 P0302 on a different make?
View P0302 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.