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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool.

2. Inspect and Replace Spark Plug

• Remove the ignition coil from cylinder 1:
  1. Disconnect the electrical connector.
  2. Remove the mounting bolts using a socket wrench.
  3. Gently lift the coil out of the spark plug well.
• Remove the spark plug:
  1. Use a spark plug socket and ratchet to unscrew the spark plug.
  2. Inspect the spark plug for wear, carbon buildup, or damage.
• Replace with a new spark plug (OEM recommended type).
• Reinstall the spark plug and ignition coil.

3. Test and Replace Ignition Coil (if needed)

• If the spark plug appears normal, test the ignition coil:
  1. Use a multimeter to check the resistance of the coil.
  2. Compare readings to manufacturer specifications.
• If out of spec, replace the ignition coil with a new one.
• Reinstall the coil and reconnect the electrical connector.

4. Inspect and Clean Fuel Injector

• Remove the fuel rail if necessary to access the fuel injector for cylinder 1:
  1. Depressurize the fuel system by removing the fuel pump fuse and running the engine until it stalls.
  2. Disconnect fuel lines and electrical connectors.
  3. Remove bolts securing the fuel rail and lift it off.
• Remove the fuel injector:
  1. Carefully pull the injector out from the cylinder head.
• Clean the injector using a professional cleaning solution or replace it if faulty.
• Reinstall the injector and reassemble the fuel rail.

5. Compression Test (if misfire persists)

• Perform a compression test on cylinder 1:
  1. Remove the spark plug from cylinder 1.
  2. Insert the compression gauge into the spark plug hole.
  3. Crank the engine and record the compression reading.
• If compression is low, diagnose potential internal engine issues (e.g., valve problems, head gasket failure).