how to diagnose P0300 misfire code in Toyota Corolla E210 (2019-2024)

Solution

1. Preparation

• Gather necessary tools and components.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool before starting work.

2. Inspect Ignition System

• Remove the engine cover (if applicable).
• Tools Required: Socket set, torque wrench.
• Remove the spark plugs using a spark plug socket.
• Inspect each spark plug for signs of wear or fouling; replace if necessary.
• Test each ignition coil with a multimeter for proper resistance. Replace any faulty coils.

3. Check for Vacuum Leaks

• Visually inspect all vacuum hoses for cracks or disconnections.
• Use a smoke machine or carburetor cleaner to check for leaks at the intake manifold and gaskets.
• Repair or replace any damaged hoses or components.

4. Examine Fuel Injectors

• Remove fuel rail assembly to access the injectors.
• Tools Required: Fuel line disconnect tool.
• Inspect and clean injectors using a fuel injector cleaner or replace them if necessary.
• Reinstall the fuel rail and ensure all connections are secure.

5. Conduct Compression Test

• Remove all spark plugs.
• Tools Required: Compression tester.
• Insert the compression tester into each cylinder and crank the engine.
• Compare compression readings across all cylinders; values should be within manufacturer specifications.
• Address any cylinders with significantly lower compression.

6. Reassemble and Test

• Reinstall spark plugs and ignition coils.
• Reattach the engine cover (if removed).
• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature.