how to fix P0300 code in my Toyota RAV4 Fifth Generation (2019-present)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool down before starting the repair.

2. Inspect and Replace Spark Plugs

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Disconnect the ignition coils from the spark plugs.
  3. Use a spark plug socket to remove the spark plugs.
  4. Inspect the spark plugs for wear and replace them if necessary (use OEM or equivalent parts).
  5. Torque the new spark plugs to OEM specifications (typically 13-16 lb-ft for Toyota).

3. Check and Replace Ignition Coils

• Sub-steps:
  1. Remove the ignition coils by unscrewing them from the cylinder head.
  2. Inspect the coils for cracks or damage; replace any faulty coils with new ones.
  3. Ensure proper connection when reinstalling the ignition coils.

4. Inspect and Clean Fuel Injectors

• Sub-steps:
  1. Remove the fuel rail with the injectors attached (ensure fuel pressure is relieved before removal).
  2. Inspect injectors for clogging; clean them using an ultrasonic cleaner or replace them if necessary.
  3. Reinstall the fuel rail and ensure all connections are secure.

5. Test Vacuum System and Repair Leaks

• Sub-steps:
  1. Use a smoke machine to identify vacuum leaks or visually inspect hoses and connections.
  2. Replace any damaged or cracked vacuum hoses.
  3. Confirm that all connections are tight and secure.

6. Verify Fuel Pressure

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "ON" position without starting the engine to check pressure.
  3. Ensure fuel pressure matches OEM specifications (usually around 50-60 psi for RAV4).
  4. Replace the fuel pump if pressure is low.