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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Ensure the vehicle is in a safe, well-ventilated area.
• Disconnect the negative battery terminal to prevent electrical hazards.

2. Replace Spark Plug

• Remove the ignition coil from cylinder 1:

  • Tools Required: Socket set, ratchet, extension.
  • Sub-steps:
    1. Unplug the electrical connector from the ignition coil.
    2. Remove the bolts securing the ignition coil and lift it out.

• Remove the spark plug:

  • Tools Required: Spark plug socket and ratchet.
  • Sub-steps:
    1. Insert the spark plug socket over the spark plug and turn counterclockwise to remove.

• Install the new spark plug:

  • Sub-steps:
    1. Apply anti-seize compound to the threads of the new spark plug.
    2. Hand-tighten the spark plug into the cylinder, then torque to the manufacturer’s specification (typically 13-15 ft-lbs).

3. Replace Ignition Coil

• If the ignition coil is found faulty, replace it:
  • Sub-steps:
    1. Install the new ignition coil onto the spark plug.
    2. Reattach the securing bolts and reconnect the electrical connector.

4. Check Fuel Injector

• If issues persist, verify or replace the fuel injector for cylinder 1:
  • Sub-steps:
    1. Disconnect the electrical connector from the fuel injector.
    2. Remove the fuel rail (if necessary) to access the injector.
    3. Replace the injector with a new one and reassemble the fuel rail.

5. Reassemble and Test

• Reconnect the battery terminal.
• Start the engine and let it reach operating temperature.
• Monitor for any check engine lights and ensure smooth operation.