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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, spark plug socket, torque wrench, fuel pressure gauge, multimeter.
• Disconnect the negative battery terminal to avoid electrical shorts.

2. Replace Spark Plugs

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Use a socket wrench to remove the spark plug wires or ignition coil connectors.
  3. Remove old spark plugs using a spark plug socket.
  4. Inspect and clean the spark plug holes to prevent debris from entering the cylinders.
  5. Install new spark plugs, ensuring they are gapped to manufacturer specifications (typically 0.043 inches for RAV4).
  6. Torque spark plugs to the manufacturer’s specification (usually around 13-15 ft-lbs).
  7. Reconnect the spark plug wires or ignition coils.

3. Check and Replace Ignition Coils

• Sub-steps:
  1. Disconnect the ignition coil connectors.
  2. Remove the ignition coils using a socket set.
  3. Test each ignition coil with a multimeter for proper resistance (usually 0.5 to 1.5 ohms for primary and 8,000 to 15,000 ohms for secondary).
  4. Replace any faulty ignition coils with new ones.
  5. Reinstall the ignition coils and reconnect the connectors.

4. Inspect and Repair Fuel System

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "ON" position (do not start) and check the fuel pressure; it should be within the manufacturer’s specifications (typically around 30-50 psi).
  3. If the pressure is low, check the fuel pump and fuel filter for issues.
  4. Replace the fuel filter if it’s clogged.
  5. If necessary, replace the fuel pump.

5. Check for Vacuum Leaks

• Sub-steps:
  1. Inspect all vacuum hoses for cracks or disconnections.
  2. Use a smoke machine or carburetor cleaner around the intake manifold and hoses to identify leaks.
  3. Replace any damaged hoses or gaskets.