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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Ensure the vehicle is parked on a level surface with the engine cooled down.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover if necessary.
  2. Disconnect the ignition coil connector for cylinder 1.
  3. Remove the ignition coil by unscrewing the retaining bolt.
  4. Remove the spark plug using a spark plug socket and ratchet.
  5. Inspect the spark plug for wear, carbon buildup, or damage.
  6. Replace with a new spark plug (OEM recommended gap).
  7. Reinstall the ignition coil and reconnect its connector.
• Tools Required: Socket set, spark plug socket, ratchet.

3. Check and Replace Ignition Coil (if necessary)

• Sub-steps:
  1. If the spark plug is fine, test the ignition coil's resistance with a multimeter.
  2. If out of specification, install a new ignition coil.
  3. Reinstall the ignition coil onto the spark plug and secure it with the retaining bolt.
  4. Reconnect the ignition coil connector.
• Tools Required: Multimeter, socket set.

4. Inspect and Test Fuel Injector

• Sub-steps:
  1. Disconnect the fuel injector connector for cylinder 1.
  2. Use a fuel injector tester to check for proper operation.
  3. Replace the injector if it does not function correctly.
  4. Reconnect the fuel injector connector after replacement.
• Tools Required: Fuel injector tester, socket set.

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 and record the compression reading.
  4. Compare the reading to manufacturer specifications; replace head gasket or repair cylinder head if low compression is found.
• Tools Required: Compression gauge, socket set.