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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool down before starting.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses for cracks or disconnections.
  2. Use a smoke machine or carburetor cleaner to detect leaks while the engine is idling.
  3. Replace any damaged hoses or gaskets found during inspection.

Tools Required:

• Smoke machine or carburetor cleaner
• Pliers
• Wrenches

3. Clean or Replace the Mass Airflow (MAF) Sensor

• Sub-steps:
  1. Disconnect the MAF sensor's electrical connector.
  2. Remove the MAF sensor from the air intake duct.
  3. Clean the MAF sensor using MAF cleaner spray; do not touch the sensor element.
  4. Reinstall the MAF sensor and reconnect the electrical connector.

Tools Required:

• Torx screwdriver
• MAF cleaner spray

4. Inspect Fuel System

• Sub-steps:
  1. Check the fuel pressure using a fuel pressure gauge; it should be within the manufacturer’s specifications (typically around 43-50 psi).
  2. If pressure is low, inspect the fuel pump, fuel filter, and fuel injectors for clogs or malfunctions.
  3. Replace the fuel filter if it hasn't been changed recently.

Tools Required:

• Fuel pressure gauge
• Wrench set
• Safety glasses

5. Check Engine Coolant Temperature (ECT) Sensor

• Sub-steps:
  1. Locate the ECT sensor and disconnect its electrical connector.
  2. Use a multimeter to test the resistance of the ECT sensor at different temperatures.
  3. Replace the ECT sensor if it does not provide the correct resistance readings.

Tools Required:

• Multimeter