how to fix P0303 misfire code on Honda Accord 10th Generation (2018-2022)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to ensure safety during repairs.
• Raise the vehicle if accessing components from underneath.

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Disconnect the ignition coil connector for cylinder 3.
  3. Remove the ignition coil by unscrewing the retaining bolts.
  4. Remove the spark plug using a spark plug socket and ratchet.
  5. Inspect the spark plug for wear or damage; replace if necessary (use OEM specifications).
  6. Install the new spark plug to the specified torque (typically around 13 lb-ft).
  7. Reinstall the ignition coil and reconnect the connector.

3. Inspect and Replace Ignition Coil

• Sub-steps:
  1. If the spark plug is fine, test the ignition coil with a multimeter.
  2. If faulty, remove the ignition coil as described above.
  3. Install the new ignition coil (ensure it’s compatible with Honda Accord 10th Gen).
  4. Reconnect the ignition coil connector.

4. Check and Replace Fuel Injector

• Sub-steps:
  1. Disconnect the battery again for safety.
  2. Remove the fuel rail if necessary to access the fuel injector for cylinder 3.
  3. Disconnect the fuel injector connector.
  4. Remove the fuel injector using a fuel injector puller or gently twisting it out.
  5. Install a new fuel injector and ensure proper seating.
  6. Reconnect the fuel rail and fuel injector connector.

5. Perform Compression Test

• Sub-steps:
  1. Remove the spark plug from cylinder 3 again for access.
  2. Insert a compression gauge into the spark plug hole.
  3. Crank the engine several times to measure the compression.
  4. Compare the compression reading to the manufacturer's specifications (should be around 180 psi).
  5. If compression is low, further diagnosis is required for internal engine issues.