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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is turned off.
• Disconnect the negative battery terminal to prevent any electrical issues during repairs.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Vacuum gauge, hose clamps, automotive spray cleaner
• Using the vacuum gauge, check the intake manifold for vacuum leaks.
• Apply the automotive spray cleaner around the intake manifold and hoses while the engine is idling. If the RPMs change, a leak is present.
• Replace any damaged hoses or gaskets identified during inspection.

3. Clean or Replace MAF Sensor

• Tools Required: MAF cleaner, torque wrench
• Locate the MAF sensor on the air intake duct.
• Disconnect the electrical connector and remove the sensor by unscrewing it.
• Use MAF cleaner to gently clean the sensor elements. Allow it to dry completely.
• Reinstall the MAF sensor, ensuring it is torqued to the manufacturer's specifications.

4. Check Fuel System Pressure

• Tools Required: Fuel pressure gauge
• Locate the fuel rail and connect the fuel pressure gauge.
• Turn on the ignition (do not start the engine) to prime the fuel system. Check the pressure reading against manufacturer specifications.
• If the pressure is low, inspect the fuel pump and fuel filter for issues, replacing them if necessary.

5. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench
• Locate the upstream and downstream oxygen sensors.
• Using the O2 sensor socket, disconnect and remove the sensors.
• Inspect the sensors for damage or corrosion. Replace them if required.
• Reinstall the new sensors and ensure they are torqued to the manufacturer's specifications.