how to fix the P0303 code in my BMW 5 Series F10/F11 (2010-2017)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Park the vehicle on a level surface and set the parking brake.
• Disconnect the battery before beginning work on the ignition system.

2. Inspect and Replace Ignition Coil

• Tools Required: Socket set, torque wrench, dielectric grease
• Remove the engine cover if applicable.
• Disconnect the electrical connector from the ignition coil for cylinder 3.
• Remove the bolts securing the ignition coil using a socket.
• Remove the ignition coil from the cylinder head.
• Inspection: Check for cracks or signs of burning on the coil.
• If faulty, replace with a new ignition coil. Apply dielectric grease to the connector before reinstalling.
• Reinstall the ignition coil and secure it with bolts, torquing to manufacturer specifications.

3. Inspect and Replace Spark Plug

• Tools Required: Spark plug socket, torque wrench
• Remove the ignition coil from cylinder 3 as previously described.
• Use a spark plug socket to carefully remove the spark plug.
• Inspection: Check the spark plug for fouling, wear, or incorrect gap.
• Replace with a new spark plug if damaged. Ensure proper gap according to manufacturer specifications.
• Reinstall the spark plug and torque to specifications.

4. Test and Replace Fuel Injector (if necessary)

• Tools Required: Fuel injector puller, torque wrench
• Disconnect the electrical connector from the fuel injector for cylinder 3.
• Remove the fuel rail if necessary to access the injector.
• Carefully remove the fuel injector from the rail or cylinder head.
• Testing: Use a multimeter to check the injector's resistance. Compare it to specifications.
• If the injector is faulty, replace it with a new one, ensuring proper seating and securing it as per specifications.