P0304 on HONDA CIVIC — Cylinder 4 Misfire Detected

Q: "What does P0304 mean on a HONDA CIVIC?"

"P0304 indicates: Cylinder 4 Misfire Detected. This is a ignition system code. 3 HONDA CIVIC owners have reported this to NHTSA."

Q: "What are the most common causes of P0304 on HONDA CIVIC?"

"Based on 3 NHTSA reports, the most commonly cited components are: Engine, Steering,Power Train,Engine. These percentages are based on the component field in owner complaints."

Q: "Is P0304 serious on my HONDA CIVIC?"

"Of 3 NHTSA reports for this code on HONDA CIVIC, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic."

Q: "What should I do if my HONDA CIVIC 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 HONDA CIVIC

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.

3 HONDA CIVIC owners have reported this issue to NHTSA across model years 2012-2018. Most reports come from the 2012, 2016 model years. The most commonly reported component is Engine (66.7% of reports).

Real HONDA CIVIC Owner Reports

Source: NHTSA Complaints Database

"Component or system failure: The vehicle experienced failures involving the engine/ignition system, emissions system, Vehicle Stability Assist (VSA), and power steering. On July 14, 2025, warning messages appeared for “Check Emissions System,” “Check VSA System,” and “Check Power Steering System."

— 2012 HONDA CIVIC owner · STEERING,POWER TRAIN,ENGINE · Filed 07/14/2025

"Driving on highway to work when check engine light came on in addition to "Emissions System Problem", "Hill Start Assist", "Power Steering Issue", etc. When scanned for codes it showed misfire codes P0300, P0301, P0302, P0303, P0304."

— 2016 HONDA CIVIC owner · ENGINE · Filed 11/11/2024

"Driving on the highway and my check engine light starting to flash. I experienced loss of power and hesitation during acceleration. I got home and scanned my computer and it returned P0304. I then removed the #4 ignition coil and that's when I noticed rust."

— 2018 HONDA CIVIC owner · ENGINE · Filed 05/24/2021

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

📊 Complaint Trend by Model Year

1

'12

1

'16

1

'18

Common Causes on HONDA CIVIC

Based on NHTSA complaint component analysis for this vehicle.

ENGINE 66.7%

STEERING,POWER TRAIN,ENGINE 33.3%

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 HONDA CIVIC? ▾

P0304 indicates: Cylinder 4 Misfire Detected. This is a ignition system code. 3 HONDA CIVIC owners have reported this to NHTSA.

What are the most common causes of P0304 on HONDA CIVIC? ▾

Based on 3 NHTSA reports, the most commonly cited components are: Engine, Steering,Power Train,Engine. These percentages are based on the component field in owner complaints.

Is P0304 serious on my HONDA CIVIC? ▾

Of 3 NHTSA reports for this code on HONDA CIVIC, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic.

What should I do if my HONDA CIVIC 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.