how to fix P0171 code on Honda Accord Eleventh Generation (2023-present)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to ensure safety during the repair process.
• Tools Required: OBD-II scanner, socket set, fuel pressure gauge, MAF sensor cleaner, multimeter.

2. Inspect and Repair Air Intake System

• Sub-steps:
  1. Remove the air intake duct to access the throttle body and MAF sensor.
  2. Inspect the duct for cracks or damage; replace if necessary.
  3. Clean the MAF sensor with MAF sensor cleaner, ensuring not to touch the sensor elements.
  4. Reinstall the air intake duct and ensure all connections are secure.

3. Check and Adjust Fuel Pressure

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition to the "ON" position without starting the engine and check the pressure reading.
  3. If the pressure is below specifications, check the fuel pump and replace it if necessary.
  4. If the pressure is adequate, proceed to check the fuel filter and replace it if it is clogged.

4. Inspect Vacuum Lines

• Sub-steps:
  1. Visually inspect all vacuum lines connected to the intake manifold for cracks or disconnections.
  2. Use a smoke machine or a vacuum leak detector to identify any hidden leaks.
  3. Replace any damaged vacuum lines to restore proper function.

5. Test Oxygen Sensors

• Sub-steps:
  1. Use a multimeter to test the voltage output of the upstream oxygen sensor while the engine is running.
  2. Compare the readings to manufacturer specifications; replace the sensor if it is out of range.
  3. Check the wiring harness and connections to ensure they are intact and free from corrosion.