why does my Honda Accord 9th Generation (2013-2017) have a check engine light and code P0171

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to ensure safety during repairs.
• Allow the engine to cool before starting work.

2. Inspect and Repair Air Intake System

• Sub-steps:
  • Visually inspect all air intake hoses and connections for cracks or looseness.
  • Tighten or replace any loose or damaged hoses.
  • Check the intake manifold for any signs of vacuum leaks.
• Tools Required: Screwdriver set, pliers

3. Check and Clean MAF Sensor

• Sub-steps:
  • Locate the MAF sensor in the air intake duct.
  • Carefully disconnect the electrical connector.
  • Remove the MAF sensor from its housing.
  • Clean the sensor using MAF sensor cleaner; do not touch the sensor element.
  • Reinstall the MAF sensor and reconnect the electrical connector.
• Tools Required: Torx or socket set, MAF cleaner
• Safety Warnings: Avoid touching the sensor element as it is sensitive and can be easily damaged.

4. Test Fuel Pressure

• Sub-steps:
  • Connect the fuel pressure gauge to the fuel rail.
  • Turn the ignition to the "ON" position (do not start the engine) and note the fuel pressure.
  • Compare the reading to the manufacturer's specifications (typically around 30-50 PSI for Honda).
• Tools Required: Fuel pressure gauge
• Safety Warnings: Relieve fuel system pressure before disconnecting fuel lines to avoid fuel spray.

5. Examine Oxygen Sensors

• Sub-steps:
  • Inspect the upstream O2 sensor wiring and connector for damage.
  • Use a multimeter to check the sensor's voltage output while the engine is running.
  • Replace the O2 sensor if it is not functioning within specifications.
• Tools Required: Multimeter, O2 sensor socket