P0303 on HYUNDAI ELANTRA — Cylinder 3 Misfire Detected

Q: "What does P0303 mean on a HYUNDAI ELANTRA?"

"P0303 indicates: Cylinder 3 Misfire Detected. This is a ignition system code. 4 HYUNDAI ELANTRA owners have reported this to NHTSA."

Q: "What are the most common causes of P0303 on HYUNDAI ELANTRA?"

"Based on 4 NHTSA reports, the most commonly cited components are: Engine, Power Train,Electrical System, Electrical System,Engine,Fuel/Propulsion System. These percentages are based on the component field in owner complaints."

Q: "Is P0303 a safety concern on HYUNDAI ELANTRA?"

"Of 4 NHTSA reports for P0303 on HYUNDAI ELANTRA, 1 involved a crash. Always consult a qualified mechanic for any diagnostic trouble code."

Q: "What should I do if my HYUNDAI ELANTRA shows P0303?"

"1) Check for recalls on your VIN at nhtsa.gov/recalls. 2) Get a professional diagnosis — a code alone doesn't identify the exact failed part. 3) Get 2-3 repair estimates to compare."

What P0303 Means on Your HYUNDAI ELANTRA

P0303 is a diagnostic trouble code indicating: Cylinder 3 Misfire Detected. This code relates to the ignition system system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

4 HYUNDAI ELANTRA owners have reported this issue to NHTSA across model years 2017-2018. Most reports come from the 2017, 2018 model years. The most commonly reported component is Engine (50.0% of reports).

Real HYUNDAI ELANTRA Owner Reports

Source: NHTSA Complaints Database

"The Issue started back in December of 2023.The Engine failed while driving to Lake Worth, TX. Vehicle Information: Model is a 2017 Hyundai Elantra Limited 2.0 Engine, US Built. Mileage during the1st incident was at 100,125 miles and the VIN Number is [XXX] ."

— 2017 HYUNDAI ELANTRA owner · ENGINE · Filed 12/04/2023

"Started having intermittent misfires on various cylinders, specifically cylinder 3. (Code P0303) This would mainly cause the engine to stall, or idle. No accidents or injuries to report, but having a car stall out at 80 MPH on the freeway is certainly scary as hell."

— 2017 HYUNDAI ELANTRA owner · POWER TRAIN,ELECTRICAL SYSTEM · Filed 08/04/2022

"Initial Fault Code: P0303 Replaced all 4 spark plugs and all 4 ignition coils. The check engine light extinguished momentarily but returned, logging P0303 and a new P0301 Replaced all 4 fuel injectors. CEL extinguished momentarily and then returned, logging P0303."

— 2018 HYUNDAI ELANTRA owner · ELECTRICAL SYSTEM,ENGINE,FUEL/PROPULSION SYSTEM · Filed 04/01/2025 ⚠️ Crash reported

"I started my vehicle and it was running sluggish and low idle. I had an engine light and when I tried to drive there was a clanking sound."

— 2018 HYUNDAI ELANTRA owner · ENGINE · Filed 06/20/2025

All reports filed by vehicle owners directly with the U.S. Department of Transportation.

📊 Complaint Trend by Model Year

2

'17

2

'18

Common Causes on HYUNDAI ELANTRA

Based on NHTSA complaint component analysis for this vehicle.

ENGINE 50%

POWER TRAIN,ELECTRICAL SYSTEM 25%

ELECTRICAL SYSTEM,ENGINE,FUEL/PROPULSION SYSTEM 25%

What To Do Next

1
Check for recalls on YOUR VIN
Go to nhtsa.gov/recalls and enter your VIN. If your vehicle is covered, repairs are free.
2
Get a proper diagnosis
A code alone doesn't tell you the exact failed part. A diagnostic at a shop ($50–$150) pinpoints the root cause before you spend money on parts.
3
Compare repair quotes
Get 2–3 quotes. Dealer vs. independent shop prices often differ 30–50% for the same repair.

Frequently Asked Questions

What does P0303 mean on a HYUNDAI ELANTRA? ▾

P0303 indicates: Cylinder 3 Misfire Detected. This is a ignition system code. 4 HYUNDAI ELANTRA owners have reported this to NHTSA.

What are the most common causes of P0303 on HYUNDAI ELANTRA? ▾

Based on 4 NHTSA reports, the most commonly cited components are: Engine, Power Train,Electrical System, Electrical System,Engine,Fuel/Propulsion System. These percentages are based on the component field in owner complaints.

Is P0303 a safety concern on HYUNDAI ELANTRA? ▾

Of 4 NHTSA reports for P0303 on HYUNDAI ELANTRA, 1 involved a crash. Always consult a qualified mechanic for any diagnostic trouble code.

What should I do if my HYUNDAI ELANTRA shows P0303? ▾

1) Check for recalls on your VIN at nhtsa.gov/recalls. 2) Get a professional diagnosis — a code alone doesn't identify the exact failed part. 3) Get 2-3 repair estimates to compare.