how to fix the P0303 code on my BMW 5 Series G30/G31 (2017-2024)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to avoid any electrical issues during the repair.

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Use a spark plug socket to carefully remove the spark plug from cylinder 3.
  3. Inspect the spark plug for signs of wear, fouling, or damage.
  4. If necessary, replace with a new spark plug (ensure it matches OEM specifications).
  5. Torque the new spark plug to the manufacturer's specifications (usually around 18-22 ft-lbs).

3. Check and Replace Ignition Coil

• Sub-steps:
  1. Disconnect the electrical connector from the ignition coil.
  2. Remove the ignition coil from cylinder 3.
  3. Inspect the coil for signs of damage or wear.
  4. If required, replace it with a new ignition coil (ensure it is compatible with your model).
  5. Reinstall the ignition coil and reconnect the electrical connector.

4. Test Fuel Injector

• Sub-steps:
  1. Disconnect the electrical connector from the fuel injector for cylinder 3.
  2. Remove the fuel injector from its rail (may require removal of the fuel rail).
  3. Inspect the injector for clogs or damage.
  4. Clean or replace the injector as necessary.
  5. Reinstall the injector and reconnect its electrical connector.

5. Conduct Compression Test (if necessary)

• Sub-steps:
  1. Remove all spark plugs to ensure accurate compression readings.
  2. Insert the compression gauge into cylinder 3.
  3. Crank the engine for a few seconds and record the compression reading.
  4. Compare the reading to the manufacturer's specifications. If low, further diagnose internal engine issues.