When your 2022 Toyota Prius displays the P0304 code, the powertrain control module has identified consistent misfires in cylinder 4. The 2022 Prius continues with the proven hybrid powertrain.
2022 Prius Hybrid System
The 2022 Prius uses the 1.8L Atkinson-cycle four-cylinder with hybrid motors producing 121 hp combined. Cylinder 4 is the rearmost on this inline-4. The engine operates intermittently.
Typical Causes
- Ignition Coil Problems: Coil-on-plug failures
- Spark Plug Condition: Hybrid-specific wear patterns
- Fuel Injector Issues: Port injection deposits
- EGR System: Exhaust gas recirculation
- Engine Cycling: Start-stop operation
Diagnostic Process
Use Toyota hybrid diagnostics. Ensure engine is running during testing. Monitor misfire counts. Port injection is simple. Test ignition components.
Repair Recommendations
Replace faulty ignition coils with Denso parts. Install properly specified spark plugs. Clean EGR system if needed.