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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Repair Vacuum Leaks

• Tools Required:
  • Vacuum gauge
  • Hose clamps
• Sub-steps:
  1. Visually inspect all vacuum hoses and connections for cracks or disconnections.
  2. Use a vacuum gauge to test the intake manifold for leaks.
  3. Replace any damaged hoses or gaskets as necessary.

3. Clean or Replace MAF Sensor

• Tools Required:
  • MAF sensor cleaner or electrical contact cleaner
  • Screwdriver set
• Sub-steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector and remove the sensor from the duct.
  3. Clean the sensor using MAF cleaner; do not touch the sensing elements.
  4. If damaged, replace the MAF sensor with a new one.

4. Check Fuel System

• Tools Required:
  • Fuel pressure gauge
  • Socket set
• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail.
  2. Turn the ignition key to the ON position (do not start) and check the pressure; it should be within manufacturer specs (typically around 40-50 psi).
  3. If the pressure is low, check the fuel pump and filter. Replace as necessary.

5. Inspect Fuel Injectors

• Tools Required:
  • Multimeter
  • Fuel injector cleaning kit (if needed)
• Sub-steps:
  1. Disconnect the fuel injector connectors.
  2. Use a multimeter to check the resistance of each injector (specifications vary by model).
  3. If any injector is out of specification, replace it. Otherwise, consider cleaning the injectors if they are clogged.

6. Replace Oxygen Sensors

• Tools Required:
  • Oxygen sensor socket
  • Wrench set
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Use the oxygen sensor socket to remove the faulty sensor(s).
  3. Install new oxygen sensors and connect the wiring.