how to fix P0301 code on Toyota Highlander XU70 (2020-Present) for cylinder 1 misfire?

Solution

1. Preparation

• Gather the necessary tools and parts.
• Ensure the vehicle is parked on a level surface with the engine off.
• Disconnect the negative battery terminal to prevent electrical shorts.

Tools Required:

• OBD-II scanner
• Socket set
• Torque wrench
• Compression tester
• Fuel injector cleaning kit (if needed)

2. Inspect and Replace Spark Plug

1. Remove the engine cover if applicable.
2. Locate the spark plug for cylinder 1.
3. Use a socket wrench to remove the spark plug.
4. Inspect the spark plug for wear, carbon buildup, or damage.
5. If the spark plug is worn or fouled, replace it with a new one, ensuring it matches the manufacturer’s specifications.
6. Torque the new spark plug to the recommended value (typically around 13-15 lb-ft).

3. Inspect and Replace Ignition Coil

1. Disconnect the electrical connector from the ignition coil for cylinder 1.
2. Remove the ignition coil from the spark plug well.
3. Inspect the ignition coil for physical damage or signs of arcing.
4. If damaged, replace the ignition coil with a new one.
5. Reinstall the ignition coil and reconnect the electrical connector.

4. Check Fuel Injector

1. Locate the fuel injector for cylinder 1.
2. Disconnect the fuel injector connector.
3. Use a multimeter to test the resistance of the injector; compare it to specifications in the service manual.
4. If the injector is faulty, remove it from the rail.
5. Replace with a new injector if necessary, ensuring proper installation.

5. Compression Test (if needed)

1. Remove the spark plug from cylinder 1.
2. Install the compression tester in the spark plug hole.
3. Crank the engine for a few seconds and record the compression reading.
4. Compare the reading to manufacturer specifications. If low, further diagnosis may be needed.