what does it mean if my Toyota RAV4 has code P0171

Solution

1. Preparation

• Gather necessary tools and materials.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Repair Air Intake System

• Sub-steps:
  • Visually inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
  • Replace any damaged hoses and re-secure connections.
  • Check the intake manifold gasket for leaks and replace if necessary.

3. Clean or Replace MAF Sensor

• Sub-steps:
  • Remove the MAF sensor carefully from the air intake duct.
  • Use MAF cleaner to spray and clean the sensor elements; do not touch the sensor with fingers.
  • Allow the sensor to dry completely before reinstalling or replace it if damaged.

4. Test and Repair Fuel System

• Sub-steps:
  • Connect a fuel pressure gauge to the fuel rail and turn the ignition to the "On" position without starting the engine.
  • Compare the fuel pressure reading to manufacturer specifications (usually between 30-50 PSI).
  • If pressure is low, check the fuel pump and filter for blockage and replace if necessary.

5. Inspect and Test Fuel Injectors

• Sub-steps:
  • Remove the fuel rail to access the injectors.
  • Inspect each injector for clogging and leakage.
  • Clean or replace any malfunctioning injectors as necessary.