how to fix the P0301 misfire code in my Honda Civic 10th Generation (2016-2021)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.

2. Replace Spark Plug

• Sub-steps:
  1. Disconnect the negative battery terminal to prevent electrical shorts.
  2. Remove the engine cover if applicable.
  3. Remove the ignition coil from cylinder 1 by disconnecting the electrical connector and unbolting it.
  4. Take out the spark plug using a spark plug socket and ratchet.
  5. Inspect the old spark plug; if it is fouled or worn, replace it with a new one. Use OEM specifications for the spark plug gap.
  6. Reinstall the ignition coil and reconnect the electrical connector.

3. Test and Replace Ignition Coil (if necessary)

• Sub-steps:
  1. Use a multimeter to test the primary resistance of the ignition coil according to OEM specifications.
  2. If the coil is out of specification, remove the old ignition coil.
  3. Install the new ignition coil in cylinder 1 and reconnect the connector.

4. Check and Replace Fuel Injector (if necessary)

• Sub-steps:
  1. Disconnect the fuel injector connector for cylinder 1.
  2. Use a multimeter to check the resistance of the injector; refer to OEM specifications.
  3. If faulty, remove the fuel rail to access the injector.
  4. Remove the old injector and install the new one, ensuring proper seating and sealing.
  5. Reconnect the fuel rail and injector connector.

5. Compression Test (if misfire persists)

• Sub-steps:
  1. Remove the spark plug from cylinder 1.
  2. Insert a compression gauge into the spark plug hole.
  3. Crank the engine for a few seconds and read the compression value.
  4. If compression is low, further diagnosis or repairs may be required, such as valve or piston work.