how to diagnose and fix P0171 lean code in my Honda Accord Eleventh Generation (2023-present)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to ensure safety during repairs.
• Tools Required: OBD-II scanner, vacuum gauge, fuel pressure gauge, MAF cleaner, socket set, torque wrench.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum lines for cracks or disconnections.
  2. Use a smoke machine or propane to identify leaks around the intake manifold and connected hoses.
  3. Replace any damaged hoses or gaskets found during inspection.

3. Check and Clean the MAF Sensor

• Sub-steps:
  1. Remove the MAF sensor from the intake duct.
  2. Spray MAF cleaner onto the sensing elements; do not touch them directly.
  3. Allow the sensor to dry completely before reinstalling it.

4. Test and Adjust Fuel Pressure

• Sub-steps:
  1. Connect the fuel pressure gauge to the Schrader valve on the fuel rail.
  2. Turn the ignition to the "ON" position (do not start the engine) and check the pressure reading against the manufacturer's specifications (typically between 40-50 psi).
  3. If the pressure is low, check the fuel pump and filter, replacing as necessary.

5. Inspect and Clean Throttle Body

• Sub-steps:
  1. Remove the intake duct from the throttle body.
  2. Use throttle body cleaner and a soft cloth to remove carbon buildup from the throttle plate and bore.
  3. Reinstall the intake duct and reconnect the battery terminal.

6. Verify Fuel Injector Functionality

• Sub-steps:
  1. Connect the fuel injector tester to the injectors.
  2. Activate each injector and check for consistent spray patterns.
  3. Replace any malfunctioning injectors.