how to fix P0302 misfire code Honda Civic 10th Generation (2016-2021)

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, multimeter, fuel injector cleaner, vacuum gauge.
• Disconnect the negative battery terminal to prevent any electrical short.
• Allow the engine to cool down before starting work.

2. Inspect and Replace Spark Plug

• Remove the ignition coil from cylinder 2:
  • Unscrew any retaining bolts using a socket set.
  • Carefully lift the ignition coil off the spark plug.
• Remove the spark plug:
  • Use the appropriate size socket to unscrew the spark plug from the cylinder head.
  • Inspect the spark plug for signs of wear (e.g., carbon buildup, wear on the electrode).
• Replace the spark plug if damaged:
  • Set the gap to the manufacturer specification (usually around 0.044 inches for Honda).
  • Install the new spark plug and torque it to the manufacturer specification (typically 13 lb-ft).

3. Check and Replace Ignition Coil

• Test the ignition coil using a multimeter:
  • Measure the primary and secondary resistance based on Honda's specifications.
  • If the resistance is out of specification, replace the ignition coil.
• Install the new ignition coil:
  • Position it correctly over the new spark plug and secure it with the retaining bolts.

4. Inspect and Clean Fuel Injector

• Remove the fuel injector from cylinder 2:
  • Disconnect the fuel injector connector.
  • Unscrew the retaining clips and pull the injector out.
• Clean the injector using a fuel injector cleaner:
  • Follow the cleaner's instructions for application.
• Reinstall the injector:
  • Ensure O-rings are lubricated with clean engine oil to prevent damage during installation.
  • Secure it back into its position.

5. Perform Compression Test

• Follow manufacturer instructions for compression testing:
  • Remove the spark plug from cylinder 2 and insert the compression tester.
  • Crank the engine and note the reading.
  • Compare the reading to manufacturer specifications.
• If the compression is low, further investigation into internal engine components may be required.