how to fix the P0301 code on my Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Gather tools and parts.
• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, multimeter, fuel injector cleaning kit.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Remove the engine cover (if applicable) to access the spark plug.
• Using a socket wrench, remove the spark plug from cylinder 1.
• Inspect the spark plug for wear; if it is worn or fouled, replace it with a new one of the manufacturer’s specifications.
• Torque the new spark plug to the manufacturer's specification (typically around 13-15 lb-ft).
• Reconnect any electrical connections and replace the engine cover.

3. Inspect and Replace Ignition Coil

• Disconnect the electrical connector from the ignition coil for cylinder 1.
• Remove the ignition coil using a socket wrench.
• Inspect for cracks or wear; if faulty, replace with a new ignition coil.
• Reinstall the ignition coil, ensuring it is seated properly.
• Reconnect the electrical connector securely.

4. Test and Clean Fuel Injector

• If the spark plug and ignition coil are functioning correctly, proceed to the fuel injector.
• Disconnect the fuel injector connector for cylinder 1.
• Use a multimeter to check the resistance of the injector; it should fall within the manufacturer-specified range.
• If the injector is clogged, use a fuel injector cleaning kit to clean it according to kit instructions.
• Reconnect the fuel injector connector after cleaning or replacing.

5. Check Compression

• Remove the spark plug from cylinder 1 again for compression testing.
• Insert the compression tester into the spark plug hole and crank the engine.
• Check the reading; it should be within the specifications provided by the manufacturer (typically around 150-200 psi).
• If compression is low, further inspection of the piston rings and valves may be necessary.

6. Reconnect Battery and Clear Codes

• Once all repairs and inspections are completed, reconnect the battery.
• Use the OBD-II scanner to clear the P0301 code.
• Start the engine and monitor for any reoccurrence of the code.