my Honda Accord 8th Generation (2008-2012) has a check engine light with code P0171

Solution

1. Preparation

• Gather tools and parts required.
• Ensure the vehicle is parked on a level surface and the ignition is off.
• Disconnect the battery to prevent electrical shorts during repairs.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses connected to the intake manifold.
  2. Use a smoke machine or carburetor cleaner to identify leaks; look for changes in engine RPM.
  3. Replace any damaged hoses or gaskets found during the inspection.

3. Fuel System Inspection

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the ON position (do not start) and check the fuel pressure against manufacturer specifications (typically between 40-50 psi for Honda).
  3. If pressure is low, inspect the fuel pump and fuel filter; replace as necessary.

4. Mass Air Flow Sensor Cleaning or Replacement

• Sub-steps:
  1. Locate the MAF sensor in the air intake pathway.
  2. Disconnect the electrical connector and remove the sensor from the housing.
  3. Clean the sensor with MAF sensor cleaner; if damaged, replace it with a new one.
  4. Reinstall the MAF sensor and reconnect the electrical connector.

5. Fuel Injector Cleaning or Replacement

• Sub-steps:
  1. Remove fuel injector connectors and unscrew the injectors from the fuel rail.
  2. Clean the injectors using an ultrasonic cleaner or replace with new ones if clogged.
  3. Reinstall the injectors and ensure all connections are secure.