what does P0171 mean for my Toyota Corolla E140 (2006-2013) and how to fix

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Vacuum gauge, basic hand tools
• Sub-steps:
  1. Use a vacuum gauge to check for vacuum pressure at the intake manifold.
  2. Inspect all vacuum hoses for cracks or disconnections; replace any damaged hoses.
  3. Apply carburetor cleaner around suspected leak areas while the engine is running to see if RPM changes, indicating a leak.

3. Clean MAF Sensor

• Tools Required: MAF sensor cleaner, Torx screwdriver
• Sub-steps:
  1. Disconnect the MAF sensor wiring harness.
  2. Remove the MAF sensor using a Torx screwdriver.
  3. Spray MAF sensor cleaner on the sensor element and let it dry completely before reinstalling.

4. Inspect and Clean Throttle Body

• Tools Required: Throttle body cleaner, soft cloth, socket set
• Sub-steps:
  1. Remove the air intake duct connected to the throttle body.
  2. Use throttle body cleaner to clean the inside of the throttle body, removing carbon buildup.
  3. Reinstall the air intake duct securely.

5. Check Fuel System

• Tools Required: Fuel pressure gauge
• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail according to the manufacturer's instructions.
  2. Turn the ignition to the ON position (without starting the engine) and check the pressure; it should meet specifications (typically around 30-40 psi for most cars).
  3. If the pressure is low, inspect the fuel pump and replace the fuel filter if clogged.