how to fix P0301 misfire code in Toyota Highlander XU70 (2020-Present)?

Solution

1. Preparation

• Gather tools and parts necessary for the repair.
• Disconnect the negative terminal of the battery to ensure safety.

2. Inspect and Replace Spark Plug

• Tools Required: Spark plug socket, ratchet, torque wrench.
• Remove the ignition coil for cylinder 1 by unscrewing the retaining bolts.
• Disconnect the electrical connector from the ignition coil.
• Remove the spark plug using a spark plug socket.
• Inspect the spark plug for wear; replace if necessary.
• If replacing, gap the new spark plug according to manufacturer specifications (generally 0.043 inches).
• Install the new spark plug and torque to the manufacturer’s specification (typically around 13-15 ft-lbs).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Inspect and Replace Ignition Coil (if necessary)

• If the ignition coil was damaged or has failed, remove it as described above.
• Replace with a new ignition coil compatible with the vehicle model.
• Reconnect the electrical connector and secure the ignition coil in place.

4. Fuel Injector Testing

• Tools Required: Fuel pressure gauge, injector cleaning kit (if cleaning is necessary).
• Test the fuel pressure at the fuel rail to ensure it meets the manufacturer specifications.
• If the injector is not functioning properly, consider cleaning or replacing the fuel injector for cylinder 1.

5. Compression Testing (if necessary)

• Tools Required: Compression gauge.
• Remove the spark plug from cylinder 1.
• Insert the compression gauge into the spark plug hole.
• Crank the engine and read the compression value; compare it to manufacturer specifications.
• If the compression is low, further investigation into engine internals may be required.