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P0304 on HONDA FIT

Severity
Medium
NHTSA Reports
7
Most Affected
2019, 2018

What P0304 Means on Your HONDA FIT

Real HONDA FIT Owner Reports (Source: NHTSA Complaints Database)

"This is after the recall on 2018-19 Fit Carbon Buildup with Misfire DTCs under codes P0300-P0304) and after fuel injectors are replaced. Current problem is with combination of carbon deposits on intake valves. Failing fuel injector/s causing an incorrect air/fuel ratio with code under P0172."

— 2018 HONDA FIT owner • ENGINE • Filed 09/03/2025

"Car is not running properly. Idling very poorly. Check engine light is on. Check engine light code is P0300, P0301, P0304. Honda has issued extended warranty for the same make/model(2018 Honda fit). My car's VIN is not included. Spoke with Honda corporate. No explanation for this."

— 2018 HONDA FIT owner • FUEL/PROPULSION SYSTEM • Filed 05/14/2024

"At 74k miles my check engine light came on randomly. Took the car to a mechanic, who turned the light off and advised me to tighten the gas cap. A few weeks later the check engine light came back on. Auto zone said a spark plug needed replacement."

— 2018 HONDA FIT owner • ENGINE,FUEL/PROPULSION SYSTEM • Filed 10/03/2023

"Four dashboard warning signs (Check Engine Light, Tire Pressure Monitoring System, Vehicle Stability Assist System, Electric Power Steering) appeared all at once suddenly. I had the vehicle towed to my local Honda dealership for service."

— 2019 HONDA FIT owner • FUEL/PROPULSION SYSTEM • Filed 11/01/2024

"All warning lights cycle through on vehicle dashboard after turning on vehicle. Vehicle was taken to Honda Auto Service Center, where issue is diagnosed as Carbon Buildup, causing misfires. Error Diagnostic Code is one of P0300 - P0304. After maintenance, error clears out."

— 2019 HONDA FIT owner • ENGINE,FUEL/PROPULSION SYSTEM • Filed 02/14/2025

Data from NHTSA Vehicle Complaints Database. All reports are filed by vehicle owners directly with the U.S. Department of Transportation.

Common Causes of P0304 on HONDA FIT

42.9%
42.9%
14.3%

Percentages based on NHTSA complaint component analysis for this vehicle.

Complaint Trend by Year

2018
3
2019
4

What To Do Next

  1. 1
    Check for recalls on YOUR VIN

    Go to nhtsa.gov/recalls and enter your VIN. Free repairs if your vehicle is covered.

  2. 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. 3
    Compare repair quotes

    Get 2-3 quotes. Dealer vs independent shop prices often differ 30-50% for the same repair.

P0304 on Other Vehicles

Data sourced from the National Highway Traffic Safety Administration (U.S. Department of Transportation) and the SAE J2012 OBD-II standard. Code definitions follow the SAE J2012 / ISO 15031-6 standard. Owner reports are filed directly with NHTSA by vehicle owners. This information is provided for educational purposes only and should not replace professional automotive diagnosis. Always consult a qualified mechanic for vehicle repair decisions.

Last updated: March 2026