When your 2022 Subaru WRX displays the P0304 code, the engine control module has detected recurring misfires in cylinder 4. The completely redesigned WRX features a new 2.4L turbocharged boxer engine requiring updated diagnostic understanding for this performance-oriented vehicle.
Understanding P0304 in the 2022 WRX
The redesigned 2022 WRX features the 2.4L FA24 turbocharged boxer four-cylinder producing 271 horsepower, replacing the previous 2.0L turbo. Subaru's horizontally-opposed configuration positions cylinder 4 at the rear of the left (driver's) bank. The performance-focused application demands precise combustion.
Performance Turbo Considerations
The WRX's sport-tuned turbo boxer operates under demanding conditions. High-RPM operation and spirited driving stress ignition components significantly. Spark plugs must reliably fire under elevated boost pressures. Performance driving accelerates normal wear patterns. Direct injection contributes to carbon accumulation potential.
Diagnostic Approach
Retrieve all codes including boost-related faults. Analyze freeze frame data noting high-RPM or high-boost conditions when misfires occurred. Locate cylinder 4 on the left bank rear position. Test ignition coil output ensuring performance capability. Inspect spark plug condition. Verify fuel injector operation.
Repair Solutions
Install Subaru-specified spark plugs rated for the performance turbo application. Clean spark plug wells before removal. Replace degraded ignition coils. Performance driving may warrant shorter maintenance intervals than standard recommendations.