how to fix P0171 lean code in Honda Civic 9th Generation (2012-2015)?

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool down before proceeding with work.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Vacuum gauge, hose clamp pliers
• Steps:
  1. Use a vacuum gauge to check for leaks in the intake manifold and vacuum hoses.
  2. Replace any damaged or cracked hoses.
  3. Re-seal gaskets that are worn or leaking.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner or isopropyl alcohol, small brush
• Steps:
  1. Disconnect the MAF sensor connector.
  2. Remove the MAF sensor using a Torx screwdriver.
  3. Clean the sensor element carefully with MAF sensor cleaner.
  4. Reinstall the MAF sensor and reconnect the electrical connector.

4. Check and Adjust Fuel Pressure

• Tools Required: Fuel pressure gauge, safety goggles
• Steps:
  1. Connect a fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "ON" position without starting the engine to check fuel pressure.
  3. If pressure is below manufacturer's specifications, check the fuel pump and filter for issues.
  4. Replace the fuel filter if clogged, and consider replacing the fuel pump if necessary.

5. Inspect Throttle Body

• Tools Required: Throttle body cleaner, soft cloth
• Steps:
  1. Remove the air intake duct connected to the throttle body.
  2. Inspect the throttle body for carbon build-up.
  3. Clean the throttle body using throttle body cleaner and a soft cloth.
  4. Reattach the intake duct securely.