how to fix P0304 code in Honda Accord 9th Generation (2013-2017)

Learn how to diagnose and fix P0304 cylinder 4 misfire in Honda Accord 9th Generation. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather the necessary tools and parts.
• Disconnect the negative terminal of the battery to ensure safety.
• Allow the engine to cool before proceeding.

2. Inspect and Replace Spark Plug

• Remove the ignition coil from cylinder 4 using a socket set.
• Extract the spark plug from cylinder 4 with a spark plug socket.
  • Tools Required: Spark plug socket, ratchet, torque wrench.
• Inspect the spark plug for signs of wear (e.g., carbon buildup, burning).
• If defective, replace the spark plug with a new one, ensuring it is gapped correctly to manufacturer specifications (typically around 0.043 inches for Honda).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Test and Replace Ignition Coil (if necessary)

• If the spark plug is fine, test the ignition coil using a multimeter to check for proper resistance (consult service manual for specific values).
• If the ignition coil is faulty, replace it with a new one.
  • Tools Required: Socket set, torque wrench.
• Reconnect the electrical connection and ensure it is securely fastened.

4. Inspect Fuel Injector

• Remove the fuel rail to access the fuel injector for cylinder 4.
  • Tools Required: Socket set, fuel injector puller if necessary.
• Check the injector for clogs or electrical issues.
• Clean or replace the injector if necessary, ensuring it seats correctly when reinstalled.

5. Conduct Compression Test

• Perform a compression test on cylinder 4.
• If compression is below specification (consult service manual for exact values), further investigation into engine internals may be required (valve seals, piston rings).