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

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool completely before starting work.

2. Inspect and Replace Spark Plug

• Remove the ignition coil for cylinder 2:
  • Use a socket set to unbolt and carefully pull the coil out.
• Remove and inspect the spark plug:
  • Use a spark plug socket to remove the spark plug.
  • Check for signs of wear, carbon buildup, or damage.
• Replace the spark plug if necessary:
  • Install a new spark plug, ensuring it is gapped correctly (check manufacturer specifications).
  • Torque the spark plug to the manufacturer's specification (usually around 20 Nm).

3. Inspect and Replace Ignition Coil

• If the spark plug is in good condition, inspect the ignition coil:
  • Look for cracks or signs of arcing.
• Replace the ignition coil if it appears faulty:
  • Install a new ignition coil on cylinder 2.
  • Reconnect the electrical connector properly.

4. Check and Replace Fuel Injector

• If misfire persists, check the fuel injector:
  • Remove the fuel rail if necessary to access the injector (make sure to relieve fuel pressure first).
• Test the injector for proper operation:
  • Use a multimeter to check the resistance of the injector (compare with specifications).
• Replace the injector if it is not functioning:
  • Install the new injector and reconnect the fuel rail.

5. Reassemble and Clear Codes

• Reconnect all components:
  • Ensure all connectors are secure.
  • Reattach the ignition coils and any removed components.
• Reconnect the battery terminal.
• Start the engine and check for smooth operation.
• Use the OBD-II scanner to clear the P0302 code.