how to resolve P0300 code in Toyota Highlander Fourth Generation (2020-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the engine is cool and disconnect the battery.

2. Inspect Spark Plugs

• Remove the ignition coils using a socket set.
• Extract the spark plugs using a spark plug socket.
• Inspect spark plugs for wear and replace if necessary.
  • Recommended spark plug gap: 0.043 inches (1.1 mm).
• Reinstall spark plugs and ignition coils, ensuring proper torque (typically 13 lb-ft or 18 Nm).

3. Check Ignition Coils

• Test each ignition coil with a multimeter for resistance.
  • Specifications: Primary resistance should be around 0.4-2.0 ohms; Secondary resistance should be around 6,000-15,000 ohms.
• Replace any faulty ignition coils.

4. Test Fuel Pressure

• Connect a fuel pressure gauge to the fuel rail.
• Turn the ignition to the "ON" position (do not start) and check the pressure.
  • Specifications: Should be around 55-62 psi (379-427 kPa).
• If pressure is low, inspect the fuel pump and fuel filter for issues.

5. Inspect Vacuum Lines

• Visually inspect all vacuum hoses for cracks or disconnections.
• Replace any damaged hoses to prevent air leaks.

6. Clean or Replace Air Filter

• Remove the air filter and check for blockages.
• Clean or replace the air filter as necessary to ensure proper airflow.