how to fix P0171 code in Honda Civic 10th Generation (2016-2021)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety during repairs.
• Allow the engine to cool down if it has been running.

2. Inspect and Repair Air Intake System

• Sub-steps:
  • Visually inspect air intake hoses for cracks or leaks.
  • Tighten any loose clamps on the air intake system.
  • Replace any damaged hoses with OEM parts.
• Tools Required: Socket set, pliers.

3. Clean or Replace MAF Sensor

• Sub-steps:
  • Locate the MAF sensor on the intake manifold.
  • Disconnect the electrical connector and remove the sensor.
  • Clean the sensor with MAF cleaner spray. If damaged, replace it with a new one.
  • Reinstall the sensor securely and reconnect the electrical connector.
• Tools Required: Torx screwdriver, MAF cleaner spray.

4. Check Fuel System

• Sub-steps:
  • Connect a fuel pressure gauge to the fuel rail.
  • Turn the ignition to the "ON" position (do not start) and observe the pressure; it should be within manufacturer specifications.
  • If pressure is low, check the fuel pump, fuel filter, and fuel injectors for proper operation.
• Tools Required: Fuel pressure gauge, socket set.

5. Inspect Oxygen Sensor

• Sub-steps:
  • Check the upstream oxygen sensor wiring for damage or corrosion.
  • Use a multimeter to test the sensor's voltage output; it should fluctuate between 0.1V and 0.9V when the engine is running.
  • Replace the oxygen sensor if it is out of spec.
• Tools Required: Multimeter, socket set.

6. Check for Vacuum Leaks

• Sub-steps:
  • Use a vacuum gauge to check for proper engine vacuum.
  • Inspect all vacuum lines for cracks or disconnections.
  • Repair or replace any damaged vacuum lines.
• Tools Required: Vacuum gauge.