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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool down before beginning work.

2. Replace Ignition Coil

1. Locate the ignition coil for cylinder 1 (refer to the vehicle's service manual for location).
2. Remove the engine cover if necessary, using a socket set.
3. Disconnect the electrical connector from the ignition coil.
4. Remove the bolt(s) securing the ignition coil and carefully pull the coil out of the spark plug well.
5. Install the new ignition coil in reverse order, ensuring it is seated properly and secure the bolts to the manufacturer's torque specifications (typically around 10 Nm).
6. Reconnect the electrical connector.

3. Replace Spark Plug

1. Remove the ignition coil again to access the spark plug.
2. Using a spark plug socket and ratchet, unscrew the spark plug from cylinder 1.
3. Inspect the old spark plug; if it is worn or fouled, replace it with a new spark plug with the correct gap (usually around 0.025-0.030 inches).
4. Install the new spark plug, ensuring it is torqued to the manufacturer’s specifications (typically around 25 Nm).
5. Reinstall the ignition coil.

4. Test Fuel Injector

1. Disconnect the fuel injector connector for cylinder 1.
2. Use a multimeter to test the injector’s resistance; it should match the specification listed in the service manual (usually around 12-16 ohms).
3. If the injector is faulty, replace it by removing the fuel rail and installing a new injector, ensuring to lubricate the O-rings before installation.

5. Final Checks

1. Reconnect the battery.
2. Start the engine and check for any sounds, misfires, or warning lights.
3. Scan for trouble codes to confirm that the P0301 code has cleared.