The P0302 trouble code on your 2020 Subaru Legacy indicates that cylinder 2 is experiencing misfires detected by the engine control module. The seventh-generation Legacy introduced for 2020 offers the 2.5L FB25D naturally aspirated boxer or the 2.4L FA24F turbocharged boxer. Both horizontally opposed engines have specific diagnostic characteristics.
2020 Legacy Engine Options
The 2.5L produces 182 horsepower while the 2.4L turbo produces 260 horsepower. Both are boxer four-cylinders with cylinder 2 on the passenger bank. Direct injection is standard on both. The turbo adds boost pressure variables to the diagnostic process.
Common Misfire Causes
Direct injection carbon buildup develops on intake valves over time. Ignition coil failure affects spark delivery. Spark plug wear or fouling—influenced by the horizontal cylinder position—reduces ignition energy. The turbo model adds potential boost-related causes. Fuel injector problems affect delivery.
Symptom Recognition
The boxer engine's distinctive sound changes with misfires. The mid-size sedan displays rough idle, vibration, and hesitation. The refined driving character suffers when cylinder 2 misfires. Check engine light accompanies the condition.
Diagnostic Process
Identify your engine type. Scan for all codes including boost codes on turbo models. Access cylinder 2 on the passenger bank. Test ignition components. Borescope inspect intake valves. Test fuel system. Compression testing verifies health.
Repair Solutions
Replace spark plugs and coils as needed. Address carbon buildup through appropriate methods. Service fuel injectors if indicated. Turbo models may require boost system evaluation.