how to fix P0300 code in my Toyota Highlander Third Generation (2014-2019)

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to ensure safety during repairs.

2. Replace Spark Plugs

• Tools Required: Socket set, torque wrench, spark plug socket
• Remove the engine cover if applicable.
• Disconnect the ignition coil connectors.
• Remove the ignition coils using the socket set.
• Unscrew and remove the old spark plugs using the spark plug socket.
• Install new spark plugs by hand, then tighten to the manufacturer's specified torque (typically 13-15 ft-lbs).
• Reinstall the ignition coils and connectors.

3. Inspect and Replace Ignition Coils (if needed)

• Tools Required: Socket set
• If spark plugs are in good condition, check ignition coils.
• Remove the faulty ignition coil and replace it with a new or known good unit.
• Reconnect the ignition coil connector.

4. Check and Clean Fuel Injectors

• Tools Required: Fuel injector cleaning kit (if applicable)
• If fuel injectors are suspected to be clogged, remove them for cleaning.
• Clean using a fuel injector cleaning solution or replace them if necessary.
• Reinstall injectors ensuring proper seating and connection.

5. Inspect Air Intake System

• Tools Required: Screwdriver set, inspection mirror
• Check for any vacuum leaks in the air intake hose and around the throttle body.
• Tighten or replace any loose or damaged hoses.
• Clean the throttle body if necessary using appropriate cleaner.