my BMW 5 Series F10/F11 (2010-2017) has a check engine light and code P0300

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to avoid any electrical issues.
• Allow the engine to cool before beginning work.

2. Spark Plug Replacement

• Tools Required: Socket set, torque wrench, spark plug socket.
• Sub-steps:
  • Remove the engine cover if applicable.
  • Disconnect the ignition coil connectors and remove the coils using the socket set.
  • Use the spark plug socket to remove the old spark plugs. Inspect them for damage or fouling.
  • Install new spark plugs, ensuring to torque them to the manufacturer’s specifications (typically around 18-22 ft-lbs).
  • Reinstall the ignition coils and reconnect the connectors.

3. Ignition Coil Inspection/Replacement

• Tools Required: Socket set, multimeter (if testing).
• Sub-steps:
  • If any ignition coils were found faulty during testing, remove the affected coils.
  • Replace with new ignition coils and ensure they are seated correctly.
  • Reconnect the battery.

4. Fuel Pressure Testing

• Tools Required: Fuel pressure gauge.
• Sub-steps:
  • Locate the fuel rail and connect the fuel pressure gauge.
  • Turn the ignition to the "ON" position without starting the engine to check the pressure (should be within manufacturer specifications).
  • Replace the fuel filter if pressure is low and the filter is due for replacement.

5. Vacuum Leak Check

• Tools Required: Smoke machine or carburetor cleaner (for manual checking).
• Sub-steps:
  • Inspect all vacuum lines visually and replace any that are cracked or damaged.
  • If using a smoke machine, apply smoke to the intake system and look for leaks.
  • Seal any leaks found and ensure proper function of the intake system.