what does it mean if my BMW 5 Series G30/G31 (2017-2024) has a P0301 misfire code

Solution

1. Preparation

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

2. Inspect and Replace Spark Plug

• Tools Required: Spark plug socket, ratchet, torque wrench.
• Remove the ignition coil from cylinder 1:
  • Disconnect the electrical connector.
  • Remove the mounting bolts and gently pull out the ignition coil.
• Remove the spark plug:
  • Use a spark plug socket to unscrew the spark plug from the cylinder head.
• Inspect the spark plug for wear, carbon buildup, or damage. Replace if necessary:
  • Install a new spark plug, ensuring it is gapped correctly (check specifications).
  • Torque to manufacturer specifications (typically around 18-22 lb-ft).

3. Inspect and Replace Ignition Coil

• If the spark plug is in good condition, inspect the ignition coil:
  • Check for cracks, corrosion, or signs of overheating.
• If replacement is needed:
  • Install the new ignition coil.
  • Reconnect the electrical connector and secure the mounting bolts.

4. Test Fuel Injector

• Check the fuel injector for cylinder 1:
  • Remove the injector connector.
  • Use a multimeter to test for resistance (refer to specifications).
• If faulty, replace the fuel injector:
  • Remove the injector from the fuel rail.
  • Install the new injector and reconnect the fuel line and electrical connector.

5. Reassembly and Testing

• Reconnect the battery.
• Start the engine and check for proper operation.
• Clear the P0301 code using the OBD-II scanner.