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

Solution

1. Preparation

• Gather tools and parts required for repair.
• Ensure the vehicle is parked on a flat surface, and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plugs

1. Remove the engine cover (if applicable) using a socket set.
2. Disconnect the ignition coil connectors.
3. Remove the bolts holding the ignition coils and carefully pull them out.
4. Use a spark plug socket to remove the spark plugs.
5. Inspect the spark plugs for wear and replace with new plugs according to manufacturer specifications (typically NGK or Denso).
6. Reinstall the spark plugs and ignition coils, ensuring a proper torque of 13 lb-ft (17.6 Nm).

3. Check and Replace Ignition Coils (if necessary)

1. If ignition coils show signs of failure, replace them one at a time.
2. Disconnect the electrical connector and remove the bolts securing the coil.
3. Install the new ignition coil and reconnect the electrical connector.

4. Fuel System Inspection

1. Use a fuel pressure gauge to check fuel pressure at the rail; it should meet manufacturer specifications (usually around 50-60 psi).
2. If pressure is low, inspect the fuel pump, fuel filter, and fuel injectors.
3. Clean or replace clogged fuel injectors.

5. Vacuum Leak Inspection

1. With the engine running, visually inspect all vacuum hoses for cracks or disconnections.
2. Use a smoke machine or carb cleaner to check for vacuum leaks and repair as needed.

6. Compression Test

1. Remove the spark plugs again and insert a compression gauge into each cylinder.
2. Crank the engine and record the compression readings; ensure they are within the manufacturer's recommended range (typically 150-200 psi).
3. If readings are low, further investigation is required for internal engine issues.