why does my Honda Civic 10th Generation (2016-2021) have a check engine light for P0300

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the battery to ensure safety while working on the vehicle.
• Allow the engine to cool down before proceeding.

2. Replace Spark Plugs

• Remove the engine cover (if applicable) using a socket set.
• Disconnect the ignition coils by unplugging the electrical connectors.
• Remove the ignition coils from the spark plug wells.
• Use a spark plug socket to carefully remove the old spark plugs.
• Install new spark plugs, ensuring they are gapped correctly according to manufacturer specifications (typically between 0.028-0.031 inches).
• Reinstall the ignition coils and reconnect the electrical connectors.

3. Test and Replace Ignition Coils (if necessary)

• If any ignition coil was found faulty during diagnostics, replace it with a new one.
• Install the new ignition coil securely in the spark plug well.
• Reconnect the electrical connector.

4. Fuel System Inspection

• If the fuel pressure test indicated low pressure, inspect the fuel pump and fuel filter.
• Replace the fuel filter if it shows signs of clogging.
• If the fuel pump is faulty, replace it according to the service manual's instructions.

5. Inspect Vacuum Lines

• Visually inspect all vacuum lines for cracks or disconnections.
• Replace any damaged vacuum hoses with new ones.
• Ensure all connections are tight and secure.