A P0304 diagnostic code on your 2019 Toyota RAV4 indicates the engine control module has detected repeated misfires in cylinder 4. The 2019 model year introduced the 5th generation RAV4 with new engines.
2019 RAV4 Powertrains
The 2019 RAV4 offers the all-new 2.5L Dynamic Force four-cylinder (203 hp) or 2.5L hybrid (219 hp). Both use D-4S dual injection. Cylinder 4 is the rearmost on these inline-4 engines.
Common Causes
- Ignition Coil Failure: Age-related degradation beginning
- Spark Plug Wear: May be approaching service interval
- Fuel Injector Issues: D-4S system concerns rare
- Carbon Buildup: D-4S helps prevent but possible
- Vacuum Leaks: Component deterioration
Diagnostic Approach
Use a Toyota-compatible scanner for detailed diagnostics. The D-4S system is reliable. Monitor misfire counts. Test ignition components systematically.
Repair Solutions
Replace ignition coils and spark plugs if approaching service interval. D-4S injectors rarely fail. Repair any vacuum leaks found.