what does it mean when my Toyota RAV4 XA50 (2019-2024) has a P0171 code?

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is on a flat surface and the engine is cool.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses and connections for damage or disconnections.
  2. If leaks are found, replace damaged hoses or reconnect loose hoses.
  3. Use a smoke machine to detect hard-to-find leaks if necessary.

3. Clean or Replace Mass Airflow Sensor (MAF)

• Tools Required: MAF cleaner or isopropyl alcohol
• Sub-steps:
  1. Disconnect the electrical connector from the MAF sensor.
  2. Remove the MAF sensor from the air intake duct.
  3. Spray MAF cleaner onto the sensor element and let it dry completely.
  4. Reinstall the MAF sensor and reconnect the electrical connector.

4. Check Fuel System

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail.
  2. Turn the ignition key to the "ON" position (do not start) and record the pressure.
  3. If the pressure is below specifications (check manufacturer specs), replace the fuel filter or inspect the fuel pump.
  4. If the fuel pressure is acceptable, check the fuel injectors for clogs by performing a flow test.

5. Replace Intake Manifold Gaskets (if necessary)

• Tools Required: Socket set, torque wrench
• Sub-steps:
  1. Remove any components obstructing access to the intake manifold.
  2. Detach the intake manifold from the engine.
  3. Clean the surface of the engine and the manifold to remove old gasket material.
  4. Install new gaskets and reassemble the intake manifold.
  5. Torque the manifold bolts to the manufacturer's specifications.