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

Solution

1. Preparation

• Tools Required: OBD-II scanner, basic hand tools, fuel pressure gauge, vacuum gauge, MAF cleaner.
• Disconnect the negative battery terminal to ensure safety during repairs.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses for cracks or disconnections.
  2. Use a vacuum gauge to test the intake manifold for any leaks.
  3. Replace any damaged hoses or gaskets found during inspection.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor, typically found between the air filter and throttle body.
  2. Disconnect the electrical connector and remove the sensor from the air intake duct.
  3. Clean the MAF sensor using MAF cleaner. Allow it to dry completely before reinstalling.
  4. If cleaning does not resolve the issue, replace the MAF sensor with a new one.

4. Check Fuel System

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "ON" position without starting the engine to check the fuel pressure. It should be within the manufacturer's specifications (usually around 40-50 psi).
  3. If pressure is low, inspect the fuel filter and replace it if necessary. If the filter is clear, check the fuel pump for malfunction.

5. Inspect Fuel Injectors

• Sub-steps:
  1. Remove the fuel rail with injectors attached.
  2. Clean the fuel injectors using a specialized injector cleaning kit.
  3. Reinstall the injectors ensuring proper seating and connections.

6. Reassemble and Reset Codes

• Reconnect the negative battery terminal.
• Clear the check engine light using the OBD-II scanner.
• Start the engine and allow it to idle, monitoring for any reoccurrence of the check engine light.