how to fix the 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 prevent electrical accidents.

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench
• Remove the engine cover if applicable.
• Use a spark plug socket to remove the spark plug from cylinder 2.
• Inspect the spark plug for wear; if damaged, replace with a new one.
• Torque the new spark plug to the manufacturer’s specification (typically 16-20 ft-lbs).

3. Replace Ignition Coil

• Tools Required: Socket set
• Disconnect the electrical connector from the ignition coil on cylinder 2.
• Remove the ignition coil using a socket.
• Install the new ignition coil, ensuring it is seated properly.
• Reconnect the electrical connector.

4. Inspect and Test Fuel Injector

• Tools Required: Fuel injector cleaning kit or multimeter
• Remove the fuel injector from cylinder 2.
• Use a multimeter to test the injector resistance (typically 12-16 ohms).
• If the injector is faulty, replace it with a new one.
• Reinstall the fuel injector and ensure proper sealing.

5. Perform Compression Test (if needed)

• Tools Required: Compression tester
• Remove the spark plugs from all cylinders.
• Insert the compression tester into cylinder 2.
• Crank the engine and record the compression reading.
• Compare the reading against manufacturer specifications (usually 140-200 psi).
• If the compression is low, further inspection of internal engine components may be necessary.