how to fix P0300 code in Toyota RAV4 Fourth Generation (2013-2018)

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, multimeter, vacuum gauge.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Inspect Ignition System

1. Remove engine cover (if applicable).
   • Use a socket set to remove any screws or bolts securing the cover.
2. Inspect spark plugs:
   • Remove spark plugs using a spark plug socket.
   • Check for wear, carbon buildup, or damage; replace if necessary.
   • Torque new plugs to manufacturer specifications (typically around 13-15 lb-ft).
3. Check ignition coils:
   • Disconnect the electrical connectors and remove the coils.
   • Test each coil with a multimeter for proper resistance; replace faulty coils.

3. Test Fuel Delivery

1. Check fuel pressure:
   • Connect a fuel pressure gauge to the fuel rail; turn the ignition to the "ON" position (do not start the engine) and check pressure against specifications (usually around 30-40 psi).
2. Inspect fuel injectors:
   • Remove and clean injectors if clogged; consider replacement if they fail to operate correctly.

4. Address Vacuum Leaks

1. Check vacuum lines:
   • Visually inspect all hoses for cracks or disconnections; replace damaged hoses.
2. Use a vacuum gauge:
   • Connect the gauge to a manifold vacuum port and read the pressure; low readings indicate leaks.

5. Perform Compression Test

1. Remove spark plugs.
2. Insert compression tester into each cylinder.
3. Crank the engine several times and record the readings:
   • Compare readings across cylinders; low compression indicates mechanical issues such as worn piston rings or valves.