how to fix P0171 code in Toyota Corolla E140 (2006-2013)

Solution

1. Preparation

• Gather the necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Clean the MAF Sensor

• Remove the MAF sensor from the air intake duct using a socket set.
• Use MAF sensor cleaner to spray the sensor elements. Avoid touching the sensor with your fingers or any tools.
• Allow the sensor to dry completely before reinstalling it.

3. Check for Vacuum Leaks

• Inspect all vacuum hoses connected to the intake manifold for signs of wear or damage.
• Replace any cracked or disconnected hoses.
• Use a smoke machine or propane gas to test for vacuum leaks around the intake manifold and gaskets.

4. Test and Replace Fuel Pressure Regulator (if needed)

• Connect a fuel pressure gauge to the fuel rail.
• Turn the ignition to the "ON" position without starting the engine and check the fuel pressure.
• If the pressure is below specifications (typically around 43-47 psi for most models), replace the fuel pressure regulator.

5. Inspect and Replace Fuel Injectors (if necessary)

• Remove the fuel rail with injectors from the engine.
• Check each injector for clogs or leaks.
• Clean or replace any faulty injectors as needed.
• Reinstall the fuel rail and ensure all connections are secure.

6. Clear Codes and Test Drive

• Reconnect the battery and use the OBD-II scanner to clear the P0171 code.
• Test drive the vehicle under various conditions to ensure the issue is resolved.