how to fix P0300 code on Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to avoid electrical shorts.

Tools Required:

• OBD-II scanner
• Socket set
• Multimeter
• Torque wrench
• Screwdrivers
• Fuel injector cleaner (if needed)

2. Inspect and Replace Spark Plugs

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Using a socket, carefully remove each spark plug.
  3. Inspect each spark plug for wear, carbon buildup, or damage.
  4. Replace with new OEM spark plugs (specify gap per manufacturer's specifications).
  5. Torque to the manufacturer's specified value (typically around 13-15 ft-lbs).

3. Test and Replace Ignition Coils

• Sub-steps:
  1. Disconnect the electrical connector from each ignition coil.
  2. Remove the ignition coils using a socket.
  3. Test each coil with a multimeter for proper resistance (usually 0.5 to 1.5 ohms).
  4. Replace any faulty ignition coils with new OEM parts.
  5. Reinstall coils and reconnect electrical connectors.

4. Inspect Fuel Injectors

• Sub-steps:
  1. Remove the fuel rail cover if present.
  2. Disconnect the fuel injector electrical connectors.
  3. Remove the fuel rail carefully, ensuring no fuel spills.
  4. Inspect injectors for clogs or leaks; clean or replace as necessary.
  5. Reinstall fuel rail and reconnect all connectors.

5. Check for Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum lines connected to the intake manifold.
  2. Check for any disconnected or damaged hoses and replace as necessary.
  3. Use a smoke tester to identify any hard-to-find leaks if necessary.