how to fix P0302 code on my BMW 3 Series E90/E91 (2005-2012)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative terminal of the battery to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil from cylinder 2 by unscrewing it.
• Remove the spark plug using the spark plug socket.
• Inspect the spark plug for wear; replace it if necessary.
• Install the new spark plug, torquing it to the manufacturer’s specifications (usually around 20 Nm for BMW).
• Reinstall the ignition coil.

3. Inspect and Replace Ignition Coil

• If the spark plug is fine, remove the ignition coil from cylinder 2.
• Test the ignition coil using a multimeter; if it is faulty, replace it with a new one.
• Reinstall the new ignition coil securely.

4. Check and Clean Fuel Injector

• Disconnect the electrical connector from the fuel injector for cylinder 2.
• Remove the fuel injector using the appropriate tools.
• Inspect for clogs; clean or replace if necessary.
• Reinstall the fuel injector and ensure it is seated correctly.

5. Compression Test

• If misfire persists, perform a compression test on cylinder 2 using a compression gauge.
• Record the readings and compare to manufacturer specifications; replace engine components if compression is low.