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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool before beginning work.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the engine cover (if applicable) to access the spark plugs.
• Disconnect the ignition coil connector from the spark plug.
• Remove the ignition coil from cylinder 2.
• Use a spark plug socket to remove the spark plug from cylinder 2.
• Inspect the spark plug for damage or excessive wear. Replace with a new spark plug if necessary, ensuring it is gapped to manufacturer specifications (typically around 0.030 inches).
• Reinstall the spark plug and torque it to the manufacturer’s specifications (usually around 18-22 ft-lbs).

3. Inspect and Replace Ignition Coil

• Tools Required: Socket set, torque wrench.
• While the ignition coil is removed, inspect it for cracks or corrosion.
• Test the ignition coil using a multimeter to ensure it meets resistance specifications (consult service manual for exact values).
• If faulty, replace the ignition coil with a new one and torque it to the manufacturer’s specifications.

4. Check Fuel Injector

• Tools Required: Fuel injector cleaner, multimeter, appropriate socket set.
• Use a multimeter to check the resistance of the fuel injector in cylinder 2 to ensure it is within specifications.
• If the injector is faulty, replace it with a new one. Clean any debris from the injector port before installation.
• Ensure all connections are secure before reassembly.

5. Final Assembly

• Reconnect the ignition coil and spark plug connectors.
• Reinstall the engine cover (if removed).
• Reconnect the negative battery terminal.