how to resolve the P0301 code in my Toyota Highlander?

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to prevent electrical shock.
• Allow the engine to cool if it has been running.

2. Inspect and Replace Spark Plug

• Remove the ignition coil from cylinder 1 using a socket set.
• Remove the spark plug using a spark plug socket and inspect for wear or damage.
• Replace the spark plug with a new one if necessary, using the torque specification of 13 lb-ft (17.6 Nm).

3. Inspect and Replace Ignition Coil

• If the spark plug is in good condition, test the ignition coil for proper operation using a multimeter.
• If faulty, remove the ignition coil and replace it with a new one. Reinstall by securing it to the cylinder head.

4. Clean or Replace Fuel Injector

• If the ignition components are functioning correctly, remove the fuel injector for cylinder 1.
• Clean the injector using a dedicated fuel injector cleaner or replace it if cleaning does not resolve the issue.
• Reinstall the injector and ensure it is securely connected.

5. Check for Vacuum Leaks

• Inspect all vacuum hoses connected to the intake manifold.
• Replace any damaged or cracked hoses.
• Use a smoke machine or carburetor cleaner to check for leaks in the intake manifold.

6. Verify Engine Compression

• If compression is low in cylinder 1, further investigation is necessary, such as checking for valve leaks or piston ring failure.
• If necessary, consult an engine repair manual for specific procedures.