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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool before starting any work.

2. Inspect and Replace Ignition Components

• Tools Required: Socket set, torque wrench, spark plug socket
• Remove the ignition coils and spark plugs.
• Inspect spark plugs for wear, fouling, or damage; replace if necessary.
• Replace any faulty ignition coils detected during the inspection.
• Reinstall the spark plugs and torque them to the manufacturer's specifications (typically around 13-16 lb-ft).

3. Fuel System Check

• Tools Required: Fuel pressure gauge
• Connect the fuel pressure gauge to the fuel rail.
• Turn the ignition to the ON position (without starting the engine) to check the fuel pressure.
• If the pressure is below specifications (usually around 43-50 PSI), inspect the fuel filter and fuel pump for issues, and replace if needed.

4. Air Intake System Inspection

• Tools Required: Screwdriver set, vacuum gauge
• Inspect the air intake duct for cracks or loose connections.
• Check for vacuum leaks using a vacuum gauge; a reading that is lower than normal indicates a potential leak.
• Clean the MAF sensor and throttle body using appropriate cleaners.

5. Compression Test

• Tools Required: Compression tester
• Remove all spark plugs and insert the compression tester into each cylinder one at a time.
• Crank the engine and record the compression readings; compare with manufacturer specifications (usually around 180-220 psi).
• If any cylinder shows significant deviation, further investigation into the internal engine components may be required.