how to fix the P0301 misfire code in my BMW 5 Series G30/G31 (2017-2024)?

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Spark Plug

1. Remove the engine cover if applicable.
2. Disconnect the ignition coil connector from the spark plug.
3. Remove the ignition coil using a socket set (typically 10mm).
4. Extract the spark plug using a spark plug socket and ratchet.
5. Inspect the spark plug for signs of wear or damage (e.g., carbon fouling, worn electrodes).
6. If necessary, replace the spark plug with a new one (use OEM specifications).
7. Reinstall the ignition coil and connect the electrical connector.

3. Inspect and Replace Ignition Coil

1. If the spark plug is in good condition, inspect the ignition coil for cracks or signs of failure.
2. If faulty, remove the ignition coil from cylinder 1.
3. Install a new ignition coil (use OEM specifications).
4. Reconnect the ignition coil electrical connector.

4. Check Fuel Injector

1. If the misfire persists, test the fuel injector for cylinder 1.
2. Disconnect the fuel injector connector.
3. Use a noid light to check for signal; if absent, troubleshoot wiring.
4. If the injector is faulty, remove and replace it (ensure to relieve fuel pressure first).
5. Reconnect the fuel injector connector.

5. Perform Compression Test

1. If the issue is still unresolved, perform a compression test on cylinder 1.
2. Remove the spark plug and connect the compression gauge.
3. Crank the engine several times and note the compression reading.
4. Compare the reading to the manufacturer's specifications; if low, further mechanical inspection is required.