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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Ensure the engine is cool before working on ignition components.

2. Replace Spark Plug

• Remove the engine cover if necessary using a socket set.
• Disconnect the ignition coil connector for cylinder 1.
• Remove the ignition coil using a socket to access the spark plug.
• Use a spark plug socket to remove the spark plug.
• Inspect the spark plug for wear and replace it with a new one (use OEM specifications).
• Install the new spark plug by threading it in by hand and then tightening to 13 lb-ft (18 Nm).
• Reinstall the ignition coil and connector.

3. Inspect and Replace Ignition Coil

• If the ignition coil appears damaged or the misfire persists, replace it.
• Remove the ignition coil from cylinder 1 as previously described.
• Install the new ignition coil, ensuring it clicks into place.
• Reconnect the ignition coil connector.

4. Fuel Injector Check

• If the problem continues, inspect the fuel injector for cylinder 1.
• Disconnect the fuel injector connector.
• Use a multimeter to check the resistance of the injector (should be within manufacturer specifications).
• If faulty, replace the fuel injector, ensuring proper seating and connection.

5. Check for Vacuum Leaks

• Inspect all hoses connected to the intake manifold for cracks or disconnections.
• Use a smoke machine or carburetor cleaner to check for leaks.
• Repair or replace any damaged hoses found.