When your 2016 Honda Civic displays the P0304 code, the powertrain control module has identified consistent misfires in cylinder 4. The 2016 model year introduced the 10th generation Civic with new engine options.
2016 Civic Engine Options
The 2016 Civic offers the 2.0L naturally aspirated (158 hp) or 1.5L turbocharged (174 hp) four-cylinder. Cylinder 4 is the rearmost cylinder on both inline-4 configurations.
Typical Causes
- Ignition Coil Degradation: Age and heat exposure cause failures
- Spark Plug Wear: Likely past or near service interval
- Fuel Injector Issues: Direct injection deposits on turbo model
- Carbon Buildup: Significant at this age on 1.5L turbo
- Valve Seal Wear: Oil consumption affecting cylinder 4
Diagnostic Process
Use Honda diagnostics for detailed access. At this age, systematic testing is important. Monitor misfire counts and check for oil consumption. Test ignition components.
Repair Recommendations
Replace ignition coils and spark plugs if not recently done. Carbon cleaning is often beneficial on turbo models at this mileage. Address any oil consumption issues.