how to fix P0302 misfire code on BMW 3 Series G20/G21 (2019-2024)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative terminal of the battery to prevent electrical shock.
• Allow the engine to cool down before proceeding.

2. Replace Spark Plug

1. Remove the engine cover to access the spark plugs.
2. Use a spark plug socket and ratchet to remove the spark plug from cylinder 2.
3. Inspect the removed spark plug for signs of wear or damage (e.g., fouling, carbon buildup).
4. Install a new spark plug, ensuring it is gapped correctly according to manufacturer specifications (typically around 0.030-0.032 inches).
5. Torque the spark plug to the manufacturer's specified value (usually around 18 lb-ft).

3. Replace Ignition Coil

1. Disconnect the electrical connector from the ignition coil for cylinder 2.
2. Remove the mounting bolt securing the ignition coil using a socket.
3. Pull the ignition coil straight out of the cylinder head.
4. Install the new ignition coil by aligning it with the spark plug and pushing it into place.
5. Reattach the mounting bolt and reconnect the electrical connector.

4. Inspect and Test Fuel Injector

1. Disconnect the fuel injector connector for cylinder 2.
2. Remove the fuel rail if necessary, securing it properly to prevent fuel spills.
3. Inspect and clean the fuel injector's nozzle; replace if damaged or blocked.
4. Reinstall the fuel injector and ensure proper connection to the fuel rail.
5. Reconnect the fuel injector electrical connector.

5. Final Assembly

1. Reinstall any components removed during the repair (e.g., engine cover).
2. Reconnect the negative terminal of the battery.
3. Clear any trouble codes using the OBD-II scanner.