how to fix a P0301 misfire code in my Toyota Corolla E210 (2019-2024)?

Solution

1. Preparation

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

2. Inspect and Replace Spark Plug

• Remove the engine cover if necessary.
• Disconnect the ignition coil connector for cylinder 1.
• Unscrew and remove the spark plug using a spark plug socket and ratchet.
• Inspect the old spark plug for wear or damage; replace if necessary.
• Install a new spark plug, ensuring it is gapped correctly according to manufacturer specifications (typically 0.044 inches for Toyota).
• Reconnect the ignition coil connector.

3. Inspect and Replace Ignition Coil

• If the spark plug is in good condition, proceed to inspect the ignition coil.
• Remove the ignition coil from cylinder 1 by unscrewing it and disconnecting the electrical connector.
• Test the ignition coil with a multimeter to ensure it is functioning correctly (typically checking primary and secondary resistance).
• Replace the ignition coil if it is faulty.
• Reinstall the ignition coil and reconnect the electrical connector.

4. Check and Clean Fuel Injector

• Access the fuel injector for cylinder 1 by removing any necessary components.
• Disconnect the fuel injector connector.
• Use a fuel injector cleaner to clean the injector (if reusable) or replace it if it is clogged or malfunctioning.
• Reinstall the injector and reconnect the wiring.

5. Final Assembly and Testing

• Reassemble any components removed during the process.
• Reconnect the battery.
• Start the engine and allow it to idle.
• Monitor for any check engine light reappearance and verify smooth engine operation.