how to resolve the P0303 code on my Honda Civic 11th Generation (2022-Present)?

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil from cylinder 3:
  • Unscrew the retaining bolts and gently pull the ignition coil out.
• Remove the spark plug:
  • Use the spark plug socket to unscrew the spark plug from cylinder 3.
• Inspect the spark plug for wear or fouling.
• If damaged, replace with a new spark plug (OEM recommended).
• Torque the new spark plug to the manufacturer's specification (typically around 13-15 lb-ft).
• Reinstall the ignition coil.

3. Check and Replace Ignition Coil

• If the spark plug was not the issue, proceed to inspect the ignition coil:
  • Use a multimeter to check the primary and secondary resistance of the ignition coil.
  • If readings are out of specification, replace the ignition coil for cylinder 3.
• Reinstall the ignition coil and reconnect any electrical connectors.

4. Inspect and Clean Fuel Injector

• If the ignition coil is functioning properly, inspect the fuel injector:
  • Disconnect the fuel injector connector.
  • Remove the fuel injector from its rail by unscrewing the retaining clips or bolts.
• Clean the injector using a fuel injector cleaner or replace if clogged or malfunctioning.
• Reinstall the fuel injector and reconnect the electrical connector.

5. Perform Compression Test

• If misfire persists, conduct a compression test:
  • Remove the spark plug from cylinder 3.
  • Insert the compression tester into the spark plug hole.
  • Crank the engine and record the compression reading.
• If compression is below specifications, further engine diagnosis may be needed for potential internal issues.