my Toyota Highlander has a P0171 code what does it mean

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle battery to ensure safety while working on electrical components.

2. Inspect and Repair Air Intake System

• Sub-steps:
  • Visually inspect all air intake hoses for signs of cracks or disconnections.
  • Use a smoke machine to identify any vacuum leaks.
  • Replace any damaged hoses or gaskets found during inspection.

3. Clean or Replace MAF Sensor

• Sub-steps:
  • Carefully remove the MAF sensor from the air intake duct.
  • Use MAF cleaner to spray the sensor elements; do not touch them.
  • Allow the sensor to dry completely before reinstallation.
  • Reinstall the MAF sensor securely.

4. Test and Repair Fuel Delivery System

• Sub-steps:
  • Connect a fuel pressure gauge to the fuel rail.
  • Start the engine and check fuel pressure against specifications (typically 30-40 psi for most Toyota engines).
  • If pressure is low, check the fuel pump and filter; replace as necessary.

5. Inspect Fuel Injectors

• Sub-steps:
  • Remove the fuel rail to access the injectors.
  • Check for clogs or leaks; clean or replace any faulty injectors.
  • Reinstall the fuel rail and ensure all connections are secure.