P0304 on KIA SELTOS — Cylinder 4 Misfire Detected

Q: "What does P0304 mean on a KIA SELTOS?"

"P0304 indicates: Cylinder 4 Misfire Detected. This is a ignition system code. 2 KIA SELTOS owners have reported this to NHTSA."

Q: "What are the most common causes of P0304 on KIA SELTOS?"

"Based on 2 NHTSA reports, the most commonly cited components are: Engine. These percentages are based on the component field in owner complaints."

Q: "Is P0304 serious on my KIA SELTOS?"

"Of 2 NHTSA reports for this code on KIA SELTOS, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic."

Q: "What should I do if my KIA SELTOS shows P0304?"

"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 P0304 Means on Your KIA SELTOS

P0304 is a diagnostic trouble code indicating: Cylinder 4 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.

2 KIA SELTOS owners have reported this issue to NHTSA across model years 2021. Most reports come from the 2021 model year. The most commonly reported component is Engine (100.0% of reports).

Real KIA SELTOS Owner Reports

Source: NHTSA Complaints Database

"My 2021 Kia Seltos (manufactured April 2020, ~94,000 miles) has the 2.0L Nu MPI engine affected by a known piston oil ring defect."

— 2021 KIA SELTOS owner · ENGINE · Filed 05/15/1999

"On [XXX], check engine light came on with P1327 (PNSS piston noise detection). History includes SC209 recall in 2021 (inspection passed, PNSS software added Feb 2022). Now at 94,000 miles with misfire P0304 on cyl 4 and timing correlation P0017—dealer refuses full engine replacement under recall."

— 2021 KIA SELTOS owner · ENGINE · Filed 02/23/2026

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

📊 Complaint Trend by Model Year

2

'21

Common Causes on KIA SELTOS

Based on NHTSA complaint component analysis for this vehicle.

ENGINE 100%

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 P0304 mean on a KIA SELTOS? ▾

P0304 indicates: Cylinder 4 Misfire Detected. This is a ignition system code. 2 KIA SELTOS owners have reported this to NHTSA.

What are the most common causes of P0304 on KIA SELTOS? ▾

Based on 2 NHTSA reports, the most commonly cited components are: Engine. These percentages are based on the component field in owner complaints.

Is P0304 serious on my KIA SELTOS? ▾

Of 2 NHTSA reports for this code on KIA SELTOS, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic.

What should I do if my KIA SELTOS shows P0304? ▾

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.