When your 2020 Honda Odyssey displays the P0304 code, the engine control module has identified consistent misfires in cylinder 4. The minivan uses Honda's proven 3.5L V6 engine.
3.5L V6 Engine Configuration
The 2020 Odyssey uses the J35Y6 3.5L V6 producing 280 horsepower with Variable Cylinder Management (VCM). Cylinder 4 is located on the rear bank of this V6.
Common Causes
- Ignition Coil Failure: Individual coil-on-plug failures
- Spark Plug Wear: Honda specifies iridium plugs
- VCM System Issues: Cylinder deactivation concerns
- Fuel Injector Problems: Direct injection deposits
- Carbon Buildup: GDI valve deposits
Diagnostic Approach
Use a Honda-compatible scanner for V6 diagnostics. Monitor VCM operation and misfire patterns. Test ignition components systematically. Check for carbon buildup symptoms.
Repair Solutions
Replace failed ignition coils with Honda OEM parts. Install properly specified spark plugs. Address VCM concerns through proper diagnosis. Consider carbon cleaning at higher mileages.