When your 2023 Toyota Highlander displays the P0304 code, the powertrain control module has identified consistent misfires in cylinder 4. The 2023 Highlander continues with proven V6 and hybrid options.
2023 Highlander Powertrains
The 2023 Highlander offers the 3.5L V6 (295 hp) or 2.5L Hybrid MAX turbo (362 hp combined). Cylinder 4 location varies by engine configuration.
Typical Causes
- Ignition Coil Problems: Coil-on-plug failures
- Spark Plug Condition: Engine-specific requirements
- Fuel Injector Issues: D-4S or turbo system
- Boost System: Turbo hybrid only
- Carbon Accumulation: D-4S helps prevent
Diagnostic Process
Use Toyota diagnostics for detailed access. The Hybrid MAX uses a turbocharged engine unlike standard hybrid. Test ignition components systematically.
Repair Recommendations
Replace faulty ignition coils with OEM parts. Install properly specified spark plugs. Hybrid MAX requires turbo-specific diagnosis.