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

Solution

1. Preparation

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

2. Inspect and Replace Spark Plugs

• Tools Required: Socket set, torque wrench, spark plug socket
• Remove the ignition coils by unscrewing the retaining bolts and disconnecting the electrical connectors.
• Remove the spark plugs using the spark plug socket.
• Inspect the spark plugs for wear or damage; replace if necessary with OEM spark plugs.
• Torque the new spark plugs to the manufacturer’s specification (usually around 13-16 lb-ft for most Toyota models).
• Reinstall the ignition coils.

3. Inspect and Replace Ignition Coils

• Check each ignition coil for cracks or corrosion.
• If faulty coils are identified, remove the damaged coils.
• Install new ignition coils, ensuring they are seated correctly and connected securely.
• Torque the ignition coil screws to manufacturer specifications.

4. Test Fuel Injectors

• Tools Required: Fuel pressure gauge, injector cleaning kit
• Check fuel pressure using the fuel pressure gauge; it should meet factory specifications (typically 50-60 PSI for Highlander).
• If fuel pressure is low, inspect the fuel filter and replace if clogged.
• Use an injector cleaning kit to clean the fuel injectors if they are suspected to be dirty or clogged.

5. Check for Vacuum Leaks

• Use the smoke test method or spray carburetor cleaner around gaskets and hoses to identify leaks.
• Replace any damaged gaskets, vacuum hoses, or intake manifold seals.

6. Clear Codes and Test Drive

• Reconnect the battery terminal.
• Use the OBD-II scanner to clear the P0300 code.
• Perform a test drive to ensure the misfire issue is resolved.