how to fix Honda Accord 10th Generation (2018-2022) with a P0171 code

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Gather safety gear including gloves and goggles.

2. Inspect for Vacuum Leaks

• Visually inspect all vacuum hoses and connections for damage or disconnections.
• Use a smoke machine or carburetor cleaner to identify leaks by spraying around suspected areas and observing engine RPM changes.

3. Fuel System Inspection

• Fuel Pressure Check:
  1. Connect a fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition key to the "ON" position (do not start the engine) and record the pressure.
  3. Start the engine and observe the fuel pressure while idling.
  4. If pressure is below specifications (usually around 40-50 psi), replace the fuel pump or filter as necessary.

4. Mass Airflow Sensor Cleaning/Replacement

• If the MAF sensor indicates low readings:
  1. Remove the MAF sensor from the intake duct.
  2. Clean the sensor elements with MAF cleaner spray (do not use other cleaners).
  3. If the sensor is damaged, replace it with a new one.

5. Fuel Injector Service

• If injectors are found to be clogged:
  1. Remove the fuel rail and injectors from the engine.
  2. Clean the injectors using an ultrasonic cleaner or replace them if necessary.
  3. Reinstall the injectors and fuel rail, ensuring all connections are tight.

6. Oxygen Sensor Check

• If oxygen sensors are failing:
  1. Disconnect the electrical connector from the sensor.
  2. Use a multimeter to check the sensor's resistance and voltage output (refer to manufacturer specifications).
  3. Replace the sensor if it does not meet specifications.