how to fix P0301 misfire code in Toyota Highlander Fourth Generation (2020-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Ensure the engine is cool before starting repairs.

2. Inspect and Replace Spark Plug

• Remove the engine cover (if applicable) using a socket set.
• Disconnect the ignition coil connector for cylinder 1 and remove the ignition coil.
• Use a spark plug socket to remove the spark plug from cylinder 1.
• Inspect the spark plug for wear; replace it if it shows signs of damage or excessive wear.
• Install the new spark plug, tightening it to the manufacturer’s specified torque (typically around 13-16 lb-ft).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Check and Replace Ignition Coil (if necessary)

• If the spark plug is in good condition, test the ignition coil with a multimeter to check resistance.
• If out of specification, remove the ignition coil and replace it with a new one.
• Ensure proper seating and reconnect the electrical connector.

4. Inspect and Clean Fuel Injector

• If the ignition components are fine, inspect the fuel injector for cylinder 1.
• Remove the fuel rail, disconnect the fuel lines (using appropriate tools), and remove the injector.
• Clean the fuel injector using a specialized cleaner or replace it if necessary.
• Reinstall the injector, ensuring it is seated correctly within the rail.

5. Reassemble and Connect Battery

• Reattach the fuel rail and reconnect any disconnected fuel lines, ensuring no leaks.
• Reinstall any engine covers removed during the process.
• Reconnect the negative battery terminal.