how to fix P0300 code in Toyota Corolla E140 (2006-2013)

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool down before starting work.

2. Inspect and Replace Spark Plugs

• Remove the ignition coil covers using a socket set.
• Disconnect the ignition coil connectors and carefully remove the coils.
• Remove the spark plugs using a spark plug socket.
• Inspect the old spark plugs for wear; replace with new spark plugs if necessary (use OEM specifications).
• Reinstall the spark plugs by hand to avoid cross-threading, then torque to manufacturer's specifications (usually around 13 lb-ft).
• Reconnect the ignition coils and connector plugs.

3. Check and Replace Ignition Coils

• If faulty coils are identified during inspection, replace them individually.
• Remove the damaged ignition coil using a socket set.
• Install the new ignition coil and reconnect the electrical connector.
• Ensure all coils are properly seated.

4. Inspect and Clean Fuel Injectors

• Remove the fuel rail if necessary to access the injectors.
• Check for clogs or leaks in the injectors.
• Clean the injectors using a professional injector cleaning kit or replace them if they are severely clogged.

5. Check Fuel Pressure

• Connect a fuel pressure gauge to the fuel rail test port.
• Turn the ignition key to the "ON" position (do not start) and check fuel pressure against the specifications (typically around 40-50 psi).
• If pressure is low, check the fuel pump and filter for issues.

6. Repair Vacuum Leaks

• Inspect all vacuum hoses visually and replace any that are cracked or damaged.
• Use a smoke machine if available to detect any hidden leaks in the intake manifold or surrounding areas.