how to fix P0304 code on Honda Accord 10th Generation (2018-2022)

Learn how to diagnose and fix P0304 cylinder 4 misfire in Honda Accord 10th Generation. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to avoid any electrical shorts.

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the engine cover if applicable.
• Disconnect the ignition coil connector for cylinder 4.
• Remove the ignition coil by unbolting it and gently pulling it out.
• Use a spark plug socket to remove the old spark plug from cylinder 4.
• Inspect the new spark plug to ensure it is gapped correctly (typically 0.043 inches for Honda).
• Install the new spark plug and torque it to the manufacturer’s specifications (usually around 13 lb-ft).
• Reinstall the ignition coil and connect the electrical connector.

3. Test and Replace Ignition Coil (if necessary)

• Tools Required: Multimeter.
• Remove the ignition coil from cylinder 4 as described above.
• Measure the primary and secondary resistance with a multimeter (refer to the vehicle service manual for specific resistance values).
• If readings are outside the specified range, replace the ignition coil with a new one.
• Reinstall the new ignition coil and reconnect the electrical connector.

4. Inspect and Clean Fuel Injector (if necessary)

• Tools Required: Fuel injector cleaning kit or new fuel injector.
• Remove the fuel injector from cylinder 4 (may require removing the intake manifold depending on access).
• Inspect for any blockages or damage; clean using a fuel injector cleaning kit if needed.
• If cleaning does not resolve the issue, replace the injector with a new one.
• Reinstall the fuel injector and ensure all connections are secure.

5. Verify Engine Health

• Perform a compression test if not already done.
• If compression is low, further engine diagnostics or repairs may be necessary.