how to fix P0302 misfire code on my BMW 5 Series G30/G31 (2017-2024)

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, multimeter, fuel injector cleaner.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shock.

2. Replace Spark Plug

1. Remove the engine cover (if applicable) using a socket set.
2. Detach the ignition coil harness from the ignition coil on cylinder 2.
3. Remove the ignition coil by unscrewing it and gently pulling it out.
4. Use a spark plug socket to remove the spark plug from cylinder 2.
5. Inspect the new spark plug for the correct gap (0.028 - 0.032 inches) and install it in cylinder 2, tightening to a torque of 15 lb-ft.
6. Reinstall the ignition coil and reconnect the harness.

3. Inspect and Replace Fuel Injector (if necessary)

1. Remove the intake manifold (if required) to access the fuel injector.
2. Disconnect the fuel injector electrical connector and fuel line (use proper safety precautions to avoid fuel spillage).
3. Remove the fuel injector from the rail and inspect for clogs or damage.
4. Clean the injector using a fuel injector cleaner or replace it with a new injector.
5. Reassemble all components, ensuring all connections are secure.

4. Compression Test (if misfire persists)

1. Remove the spark plug from cylinder 2.
2. Insert the compression tester into the spark plug hole.
3. Crank the engine for several seconds and record the compression reading.
4. Compare the reading to the manufacturer’s specifications. If low, further investigation into engine internals may be necessary.