how to diagnose my BMW 3 Series F30/F31 (2012-2019) with a misfire code P0302

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, compression tester, spark plug socket.
• Safety Warnings: Disconnect the battery before working on the ignition system.

2. Replace Spark Plug

• Remove Spark Plug: Use a spark plug socket to remove the spark plug from cylinder 2.
• Install New Spark Plug: Install a new spark plug (ensure it matches the manufacturer specifications) and torque it to the specified value (usually around 25 Nm).

3. Replace Ignition Coil (if necessary)

• Remove Ignition Coil: Disconnect the electrical connector and remove the ignition coil from cylinder 2.
• Install New Ignition Coil: Position the new ignition coil and secure it in place. Reconnect the electrical connector.

4. Clean or Replace Fuel Injector (if necessary)

• Remove Fuel Injector: Disconnect the fuel line and electrical connector, and remove the fuel injector from cylinder 2.
• Inspect and Clean: Clean the injector using a suitable injector cleaner or replace it with a new one if it is defective.
• Reinstall Injector: Install the injector and reconnect the electrical connector and fuel line.

5. Reconnect Battery and Clear Codes

• Reconnect the battery and use the OBD-II scanner to clear the P0302 code from the vehicle's computer.