why does my Honda Civic 10th Generation (2016-2021) have a check engine light and P0171 code

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.
• Allow the engine to cool down before starting work.

2. Inspect Intake System

• Tools Required: Vacuum gauge, basic hand tools
• Instructions:
  1. Visually inspect all vacuum hoses for cracks or disconnections.
  2. Use a vacuum gauge to check for vacuum leaks.
  3. Replace any damaged hoses or gaskets found during inspection.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, Torx or socket set
• Instructions:
  1. Disconnect the electrical connector from the MAF sensor.
  2. Remove the MAF sensor from the intake duct.
  3. Spray the sensor with MAF cleaner and allow it to dry.
  4. Reinstall the MAF sensor and reconnect the electrical connector.

4. Inspect Fuel System

• Tools Required: Fuel pressure gauge
• Instructions:
  1. Locate the fuel rail and connect the fuel pressure gauge.
  2. Turn the ignition to the "ON" position without starting the engine and check the pressure.
  3. Compare the reading with the manufacturer’s specifications; replace the fuel pump if pressure is low.

5. Check Fuel Injectors

• Tools Required: Multimeter, injector cleaner
• Instructions:
  1. Disconnect the fuel injector connectors.
  2. Use a multimeter to check the resistance of each injector (should be within specifications).
  3. If an injector is faulty, replace it or use injector cleaner to unclog.

6. Verify Oxygen Sensor Operation

• Tools Required: OBD-II scanner, multimeter
• Instructions:
  1. Connect an OBD-II scanner to monitor live data for the oxygen sensors.
  2. Check the voltage readings; they should fluctuate between 0.1V and 0.9V.
  3. Replace any faulty oxygen sensors based on the readings.