When your 2024 BMW 3 Series displays diagnostic trouble code P0306, the engine control module has detected misfires in cylinder 6. If your 3 Series is equipped with an inline-6 engine option such as the M340i, this is a valid diagnostic code requiring BMW-specific troubleshooting procedures.
2024 BMW 3 Series Engine Options
The 2024 BMW 3 Series offers multiple engine configurations. The M340i and M340i xDrive use the B58 3.0-liter turbocharged inline-6 producing 382 horsepower. This engine has six cylinders, making P0306 a valid code. Base models with four-cylinder engines cannot have legitimate P0306 codes.
BMW B58 Inline-6 Configuration
The B58 inline-6 positions cylinder 6 at the rear of the engine closest to the firewall. BMW's advanced ignition system uses individual coils with integrated ignition modules. The turbocharged direct-injection system adds complexity to misfire diagnosis.
Common P0306 Causes on B58
Ignition coil failure is the most common cause, though BMW coils are generally reliable. Spark plug wear, particularly with high-mileage vehicles, causes misfires. Direct injection carbon buildup on intake valves can affect cylinder 6. Fuel injector problems, though less common, can cause lean misfires.