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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety while working with electrical components.

2. Replace Ignition Coil

• Remove the engine cover to access the ignition coils.
• Disconnect the electrical connector from the ignition coil for cylinder 2.
• Remove the bolt securing the ignition coil using a socket set.
• Pull out the ignition coil from the spark plug well.
• Install the new ignition coil into the spark plug well and secure it with the bolt.
• Reconnect the electrical connector.

3. Replace Spark Plug

• Use a spark plug socket to remove the spark plug from cylinder 2.
• Inspect the old spark plug for wear or fouling.
• Adjust the gap on the new spark plug to the manufacturer's specification (usually around 0.028-0.032 inches).
• Install the new spark plug into cylinder 2 and torque it to the manufacturer's specification (typically around 15 ft-lbs).

4. Inspect/Replace Fuel Injector (if necessary)

• Locate the fuel rail and disconnect the fuel line (use a rag to catch any fuel spillage).
• Remove the retaining clips and disconnect the electrical connector from the fuel injector for cylinder 2.
• Remove the fuel injector from the rail.
• Inspect the injector for clogs; replace if necessary.
• Install the new or cleaned injector, reattach the electrical connector, and secure the fuel line.

5. Reassemble and Test

• Reinstall the engine cover.
• Reconnect the negative battery terminal.
• Start the engine and check for codes; allow the engine to idle and monitor for any misfire symptoms.