how to fix a P0302 code on my BMW X3 F25 (2011-2018)

Solution

1. Preparation

• Gather tools and materials.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool down.

Tools Required:

• OBD-II scanner
• Socket set
• Torque wrench
• Compression tester
• Vacuum gauge

2. Replace Spark Plug

• Remove the ignition coil for cylinder 2 by unscrewing the retaining bolts and unplugging the electrical connector.
• Extract the old spark plug using a spark plug socket.
• Inspect the spark plug gap and replace it with a new spark plug if it shows signs of wear or damage.
• Install the new spark plug by hand, then torque to manufacturer specifications (typically around 20 Nm / 15 ft-lb).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Check and Replace Ignition Coil

• If the spark plug is in good condition, test the ignition coil using a multimeter to check for proper resistance.
• If the ignition coil is faulty, remove it and replace it with a new coil for cylinder 2.
• Follow the reinstallation procedure as outlined in the previous step.

4. Compression Test

• Remove the spark plug from cylinder 2 and insert the compression tester.
• Crank the engine for a few seconds and record the pressure reading.
• Compare the reading to manufacturer specifications (generally between 120-200 psi) to determine if there are any mechanical issues.

5. Inspect Fuel Injector

• If the compression is adequate, check the fuel injector for cylinder 2 by removing it from the fuel rail.
• Clean or replace the injector if it appears clogged or defective.
• Reinstall the fuel injector and secure it properly.