how to fix P0300 code in Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect Spark Plugs

• Tools Required: Spark plug socket, ratchet, torque wrench.
• Steps:
  1. Remove the engine cover if necessary.
  2. Disconnect the ignition coil connectors.
  3. Remove the ignition coils.
  4. Unscrew the spark plugs using the spark plug socket.
  5. Inspect spark plugs for wear, fouling, or damage. Replace if necessary, using NGK or Denso plugs as recommended by the manufacturer.
  6. Reinstall new spark plugs, torquing them to the manufacturer’s specifications (typically around 13 lb-ft).

3. Inspect Ignition Coils

• Tools Required: Multimeter.
• Steps:
  1. Test each ignition coil using the multimeter for resistance checks. The primary circuit should read around 0.4-2 ohms; the secondary circuit should be around 6,000-15,000 ohms.
  2. Replace any faulty ignition coils with OEM parts.
  3. Reconnect ignition coils and connectors.

4. Check Fuel System

• Tools Required: Fuel pressure gauge.
• Steps:
  1. Connect the fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the “ON” position without starting the engine to check fuel pressure. It should meet specifications (typically around 50-60 psi).
  3. If pressure is low, inspect the fuel filter and fuel pump for issues and replace as necessary.

5. Inspect Air and Vacuum Systems

• Tools Required: Visual inspection tools.
• Steps:
  1. Visually inspect the air intake system for blockages or leaks.
  2. Check vacuum lines for cracks or disconnections.
  3. Repair or replace any damaged components.