my Honda Civic 10th Generation (2016-2021) has a check engine light with code P0301

Solution

1. Preparation

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

2. Inspect and Replace Spark Plug

• Remove the ignition coil from cylinder 1 using a socket set.
• Remove the spark plug using a spark plug socket and ratchet.
  • Tools Required: Spark plug socket, ratchet, torque wrench
• Inspect the spark plug for wear or fouling. If necessary, replace with a new spark plug (OEM recommended).
• Torque the new spark plug to the manufacturer's specification (typically around 13 lb-ft).

3. Inspect and Replace Ignition Coil

• If the spark plug is in good condition, inspect the ignition coil for cracks or damage.
• If needed, replace the ignition coil for cylinder 1 by removing it from the spark plug well.
  • Tools Required: Socket set
• Install the new ignition coil and ensure it is seated properly.

4. Inspect Fuel Injector

• Remove the fuel rail cover and inspect the fuel injector for cylinder 1.
• If the injector appears clogged, use a fuel injector cleaning kit or replace the injector.
  • Tools Required: Fuel injector cleaner kit or replacement injector
• Reinstall the fuel rail and ensure all connections are secure.

5. Check Engine Compression

• If misfire persists, perform a compression test on cylinder 1.
  • Remove the spark plug and attach the compression tester.
  • Crank the engine and read the pressure. Compare with specifications (typically 180-200 psi).
• If compression is low, further investigation into engine internals may be required.