how to fix P0303 misfire code in Honda Accord Eleventh Generation (2023-present)

Solution

1. Preparation

• Gather tools and parts required.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool before starting work.

2. Inspect and Replace Spark Plug

• Tools Required: Spark plug socket, torque wrench, extension bar.
• Remove the ignition coil for cylinder 3.
• Use the spark plug socket to remove the spark plug. Inspect for signs of wear or carbon buildup.
• If the spark plug is damaged, replace it with a new plug that meets OEM specifications.
• Torque the new spark plug to the manufacturer's specified value (typically around 13-16 lb-ft).
• Reinstall the ignition coil.

3. Inspect and Replace Ignition Coil

• Tools Required: Socket set, multimeter (optional).
• If the ignition coil appears damaged or you suspect it is faulty, remove it from cylinder 3.
• Test the coil's resistance using a multimeter (if applicable) to ensure it’s within specifications.
• Replace with a new ignition coil if necessary.
• Reinstall the ignition coil securely.

4. Inspect Fuel Injector

• Tools Required: Fuel injector cleaning kit (if needed), socket set.
• Remove the fuel injector for cylinder 3.
• Inspect the injector for clogs or damage.
• Clean the injector if it appears dirty using a fuel injector cleaning kit.
• Reinstall or replace the injector as needed.

5. Perform Compression Test

• Tools Required: Compression tester.
• Remove the spark plug from cylinder 3.
• Insert the compression tester into the spark plug hole.
• Crank the engine and record the compression reading. Compare with specifications.
• If compression is low, further investigation into the cylinder head or piston rings may be necessary.