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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Repair Vacuum Leaks

• Visually inspect all vacuum hoses and connections for cracks or disconnections.
• Use a smoke machine or carburetor cleaner to identify any vacuum leaks by spraying around suspected areas.
• If a leak is found, replace the damaged hose or reattach any loose connections.

3. Fuel System Inspection

• Check Fuel Pressure:

  • Connect a fuel pressure gauge to the fuel rail's test port.
  • Turn the ignition to the "ON" position without starting the engine and check the pressure. It should be within the manufacturer’s specifications (usually around 40-50 psi).
  • If the pressure is low, replace the fuel pump or fuel filter if blocked.

• Inspect Fuel Injectors:

  • Remove the fuel rail and inspect each injector for clogs or leaks.
  • Use a multimeter to test the resistance of each injector (should typically be around 12-16 ohms).
  • Clean or replace any faulty injectors.

4. MAF Sensor Cleaning

• Locate the MAF sensor on the air intake.
• Carefully remove the sensor from its housing.
• Use MAF sensor cleaner to clean the sensor element (do not touch it with hands or tools).
• Reinstall the MAF sensor and ensure the connections are secure.

5. Reassemble and Reset System

• Reconnect all components removed during the repair process.
• Reconnect the negative battery terminal.
• Start the engine and let it idle for a few minutes.