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 cable to prevent electrical shorts.

2. Replace Spark Plug

• Remove the engine cover if applicable.
• Locate the ignition coil and spark plug for cylinder 1.
• Use a spark plug socket and ratchet to remove the spark plug.
• Inspect the old spark plug for wear or damage; replace it with a new, manufacturer-specified spark plug.
• Torque the new spark plug to the manufacturer's specification (typically around 13-15 ft-lbs).

3. Inspect and Replace Ignition Coil

• Remove the ignition coil from cylinder 1 by unscrewing the retaining bolts.
• Inspect the ignition coil for physical damage or signs of arcing.
• If the coil is defective, replace it with a new ignition coil that matches OEM specifications.
• Reinstall the ignition coil and torque it to the manufacturer’s specifications.

4. Test Fuel Injector

• Disconnect the electrical connector from the fuel injector for cylinder 1.
• Use a multimeter to check for proper voltage and resistance according to manufacturer specifications.
• If the injector is faulty, remove it using an injector puller and replace it with a new one.
• Reconnect the electrical connector after replacement.

5. Reassemble and Final Inspection

• Reinstall any components removed during the process (engine cover, etc.).
• Reconnect the negative battery cable.
• Clear the DTC using an OBD-II scanner.