The P0304 code in your 2022 Subaru Impreza indicates the powertrain control module has detected persistent misfires in cylinder 4. Understanding the compact car's boxer engine configuration enables targeted diagnosis for effective repair of this combustion problem.
Understanding P0304 in the 2022 Impreza
The 2022 Impreza features the 2.0L FB20 boxer four-cylinder. Subaru's horizontally-opposed design positions cylinder 4 at the rear of the left (driver's) bank. This unique engine architecture affects both diagnostic approach and service accessibility compared to inline engines.
Boxer-Specific Considerations
The flat-four boxer mounts spark plugs horizontally. This orientation can allow debris and moisture accumulation in spark plug wells. Standard ignition wear—coil degradation and plug electrode erosion—represents the most common P0304 cause. The configuration requires Subaru-specific service approaches.
Diagnostic Process
Retrieve all codes and analyze freeze frame data. Locate cylinder 4 at the rear of the left bank. Working space may be limited in the compact engine bay. Test ignition coil output and spark plug condition. Verify fuel injector operation through appropriate methods.
Repair Implementation
Install Subaru-approved spark plugs at proper torque. Clean around plug wells thoroughly before removal. Replace degraded ignition coils. Address fuel system concerns as identified during diagnosis.