how to fix the P0171 code in my Toyota RAV4 Fourth Generation (2013-2018)?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on the vehicle.
• Allow the engine to cool if it has been running.

2. Inspect and Repair Air Intake System

• Tools Required: Socket set, screwdrivers
• Sub-steps:
  1. Visually inspect all vacuum hoses connected to the intake for cracks or disconnections.
  2. Tighten any loose clamps on the intake system.
  3. Replace any damaged hoses or gaskets found during inspection.

3. Check and Clean the MAF Sensor

• Tools Required: MAF sensor cleaner
• Sub-steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector from the MAF sensor.
  3. Remove the MAF sensor using a screwdriver.
  4. Spray the MAF sensor thoroughly with MAF cleaner and allow it to dry completely before reinstallation.
  5. Reinstall the MAF sensor and reconnect the electrical connector.

4. Test Fuel Pressure

• Tools Required: Fuel pressure gauge
• Sub-steps:
  1. Locate the fuel rail and connect the fuel pressure gauge to the test port.
  2. Turn the ignition to the "ON" position (do not start the engine) and check the pressure reading.
  3. Compare the reading to the manufacturer's specifications (typically around 40-50 psi for most Toyota models).
  4. If the pressure is low, check the fuel pump, filter, and relay for issues.

5. Inspect Fuel Injectors

• Tools Required: Fuel injector cleaner, multimeter (if testing injector resistance)
• Sub-steps:
  1. Remove the fuel rail to access the fuel injectors.
  2. Inspect the injectors for clogs or leaks.
  3. Clean the injectors using a fuel injector cleaning kit if necessary.
  4. Test the injectors' electrical connections with a multimeter for proper resistance (typically around 12-16 ohms).

6. Verify Oxygen Sensor Function

• Sub-steps:
  1. Check the wiring and connectors of the upstream oxygen sensor for damages.
  2. Test the sensor's voltage output with a multimeter while the engine is running.
  3. Replace the oxygen sensor if it is outside the manufacturer's specified range.