how to fix P0171 code in my Toyota RAV4 Fifth Generation (2019-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to avoid electrical issues.
• Allow the engine to cool before working on it.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  • Inspect all vacuum hoses for cracks or disconnections.
  • Use a smoke machine or carburetor cleaner around the intake manifold and hoses to locate leaks.
  • Replace any damaged hoses or gaskets found during the inspection.

3. Clean or Replace MAF Sensor

• Sub-steps:
  • Remove the MAF sensor from the air intake duct using a suitable socket.
  • Clean the MAF sensor with MAF cleaner, avoiding touching the sensor elements.
  • If cleaning does not resolve the issue, replace the MAF sensor with a new one.

4. Check and Adjust Fuel Pressure

• Sub-steps:
  • Connect a fuel pressure gauge to the fuel rail test port.
  • Turn the ignition on (without starting the engine) to check the fuel pressure. It should be within the manufacturer’s specifications (typically between 50-60 psi).
  • If the pressure is low, inspect the fuel pump and fuel filter for issues and replace if necessary.

5. Inspect and Test Fuel Injectors

• Sub-steps:
  • Remove the fuel rail to access the injectors.
  • Inspect the injectors for clogs or leaks.
  • Use a multimeter to test the resistance of the injectors. Replace any that are out of specification.

6. Replace Faulty Oxygen Sensors (if needed)

• Sub-steps:
  • Identify the oxygen sensor(s) associated with bank 1.
  • Use an oxygen sensor socket to remove the faulty sensor.
  • Install the new oxygen sensor and ensure it is properly connected.