how to fix the P0171 code on my Honda Civic 10th Generation (2016-2021)

Solution

1. Preparation

• Gather tools: OBD-II scanner, vacuum gauge, fuel pressure gauge, multimeter, socket set, cleaning supplies (MAF cleaner), and safety gear.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
  2. Use a vacuum gauge to test the intake manifold vacuum; it should be within manufacturer specifications.
  3. If leaks are found, replace the damaged hoses or gaskets as needed.

3. Clean or Replace the MAF Sensor

• Sub-steps:
  1. Disconnect the MAF sensor electrical connector.
  2. Remove the MAF sensor from the air intake duct using the appropriate socket.
  3. Spray MAF cleaner on the sensor elements and allow it to dry completely.
  4. Reinstall the MAF sensor and reconnect the electrical connector.

4. Check Fuel Pressure

• Sub-steps:
  1. Locate the fuel pressure test port on the fuel rail.
  2. Connect the fuel pressure gauge to the test port.
  3. Turn the ignition to the "ON" position (do not start the engine) and check the pressure reading against specifications.
  4. If pressure is low, inspect the fuel pump and filter for proper operation and replace as necessary.

5. Inspect and Test Fuel Injectors

• Sub-steps:
  1. Remove the fuel injector connectors.
  2. Use a multimeter to check the resistance of each injector; compare with specifications.
  3. If any injector is out of specification, replace it.
  4. Clean the fuel injectors using a professional injector cleaning service if necessary.

6. Replace the ECT Sensor (if faulty)

• Sub-steps:
  1. Locate the ECT sensor on the engine.
  2. Disconnect the electrical connector and remove the sensor using the appropriate socket.
  3. Install the new ECT sensor, ensuring a proper seal with new O-rings.
  4. Reconnect the electrical connector.