what causes the P0302 code on my BMW 3 Series E90/E91 (2005-2012)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to avoid electrical shorts during the repair.
• Allow the engine to cool before working on the ignition system.

2. 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 2.
• Unbolt and remove the ignition coil from the cylinder head.
• Install the new ignition coil, ensuring it is seated properly.
• Reconnect the electrical connector and apply dielectric grease to prevent moisture intrusion.

3. Replace Spark Plug

• Tools Required: Spark plug socket, torque wrench
• Remove the ignition coil again if previously removed.
• Use a spark plug socket to remove the spark plug from cylinder 2.
• Inspect the old spark plug for wear, and install a new spark plug with the correct gap (check manufacturer specifications).
• Torque the spark plug to the manufacturer’s specification.
• Reinstall the ignition coil.

4. Test and Replace Fuel Injector (if necessary)

• Tools Required: Fuel injector puller (if needed), cleaning solvent
• Disconnect the fuel injector connector for cylinder 2.
• Remove the fuel rail if necessary to access the injector.
• Carefully remove the fuel injector from the rail or cylinder head.
• Inspect and clean the injector or replace it with a new one.
• Reassemble the fuel rail and reconnect all connectors.