how to diagnose a misfire in my Honda Civic 9th Generation (2012-2015) with code P0302?

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Remove the ignition coil from cylinder 2 using a socket set.
• Remove the spark plug from cylinder 2 using a spark plug socket.
• Inspect the spark plug for wear or damage; replace if necessary.
• Install a new spark plug into cylinder 2, torque to manufacturer specifications (typically 13-16 lb-ft).
• Reinstall the ignition coil and ensure it is seated properly.

3. Test and Replace Ignition Coil (if necessary)

• If the spark plug is in good condition, use a multimeter to test the ignition coil resistance.
• If the resistance is out of specification, replace the ignition coil with a new one.
• Reinstall the ignition coil and ensure connections are secure.

4. Check and Replace Fuel Injector (if necessary)

• Disconnect the fuel injector connector for cylinder 2.
• Test the injector's resistance with a multimeter; it should typically be around 12-16 ohms.
• If the injector fails the test, replace it with a new one.
• Reconnect the fuel injector and ensure it is seated properly.

5. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0302 code from the memory.