why does my BMW 5 Series F10/F11 (2010-2017) have a check engine light with code P0302

Solution

1. Preparation

• Gather necessary tools and parts before starting.
• Disconnect the battery to avoid electrical shocks or shorts.
• Allow the engine to cool if it has been recently operated.

2. Inspect and Replace Spark Plug

• Tools Required: Spark plug socket, ratchet, torque wrench.
• Remove the ignition coil from cylinder 2 by unbolting it and carefully pulling it out.
• Use a spark plug socket to remove the spark plug from cylinder 2.
• Inspect the spark plug for signs of fouling or wear. If damaged, replace it with a new one.
• Torque the new spark plug to the manufacturer's specification (typically around 20 Nm).

3. Inspect and Replace Ignition Coil

• If the spark plug is in good condition, proceed to inspect the ignition coil.
• Disconnect the electrical connector from the ignition coil and remove the mounting bolts.
• Replace the ignition coil with a new one if it's found to be faulty.
• Ensure the new ignition coil is seated properly and reconnect the electrical connector.

4. Check Fuel Injector

• Tools Required: Fuel injector cleaning kit (if needed), multimeter.
• Disconnect the fuel injector connector from cylinder 2.
• Use a multimeter to check the resistance of the fuel injector; it should match the specifications in the service manual.
• If the injector is faulty, replace it with a new one.
• Reconnect the fuel injector connector after replacement.

5. Perform Compression Test (if necessary)

• If issues persist after replacing the spark plug and ignition coil, conduct a compression test on cylinder 2.
• Use a compression gauge to measure the cylinder pressure.
• Compare the reading to the specifications; low compression may indicate internal engine problems such as a blown head gasket or valve issues.