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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, fuel pressure gauge, socket set, torque wrench, MAF cleaner.
• Disconnect the negative battery terminal.
• Allow the engine to cool down before starting work.

2. Inspect Air Intake System

• Remove the air intake duct.
• Visually inspect for cracks or loose connections.
• Using a smoke machine, check for vacuum leaks.
• Tighten any loose connections or replace damaged hoses.

3. Clean or Replace MAF Sensor

• Locate the MAF sensor in the air intake path.
• Disconnect the electrical connector and remove the sensor using the appropriate socket.
• Spray MAF cleaner on the sensor element; do not touch it with your fingers.
• Allow it to dry completely, then reinstall the sensor and reconnect the electrical connector.

4. Check Fuel System

• Fuel Pressure Test:
  • Connect the fuel pressure gauge to the fuel rail.
  • Turn the ignition on (do not start) and record the pressure reading.
  • Compare the reading to the manufacturer's specifications (typically between 43-50 psi).
• If pressure is low, check the fuel pump and filter for clogs or failure, and replace as necessary.

5. Inspect and Clean Fuel Injectors

• If fuel pressure is normal, remove the fuel injectors.
• Clean them using an ultrasonic cleaner or injector cleaning kit.
• Reinstall the injectors and ensure all seals are intact.

6. Reassemble and Test

• Reinstall all components in reverse order of removal.
• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature.