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

Solution

1. Preparation

• Gather tools and parts required.
• Disconnect the negative battery terminal to prevent electrical shock.

2. Inspect and Replace Spark Plugs

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the engine cover if necessary.
• Use the spark plug socket to remove the spark plugs.
• Inspect the spark plugs for signs of wear, fouling, or damage.
• Replace spark plugs with OEM parts, ensuring the correct gap.
• Torque the new spark plugs to the manufacturer's specifications (typically 13-16 ft-lbs).

3. Inspect and Replace Ignition Coils

• Tools Required: Socket set, multimeter.
• Disconnect the wiring harness from the ignition coils.
• Remove the ignition coils using the socket set.
• Test the ignition coils with a multimeter for proper resistance (refer to the service manual for specific values).
• Replace any faulty coils with new OEM coils.
• Reinstall the ignition coils and reconnect the wiring harness.

4. Check Fuel Injectors

• Tools Required: Fuel pressure gauge, multimeter.
• Connect the fuel pressure gauge to the fuel rail and turn the ignition to the "ON" position to check pressure.
• If pressure is low, inspect the fuel pump and filter.
• Test each fuel injector with the multimeter to ensure they are receiving power and functioning correctly.
• Replace any faulty fuel injectors.

5. Inspect Vacuum Lines

• Tools Required: Visual inspection tools, smoke machine (optional).
• Conduct a visual inspection of vacuum lines for any cracks or disconnections.
• If necessary, use a smoke machine to detect hard-to-find leaks.
• Replace any damaged vacuum hoses.