how to fix P0171 code on my Toyota RAV4 XA40 (2013-2018)

Solution

1. Preparation

• Gather tools and parts: OBD-II scanner, fuel pressure gauge, MAF cleaner, multimeter, socket set, and safety gloves.
• Disconnect the negative battery cable to prevent electrical shorts.

2. Inspect Air Intake System

• Sub-steps:
  1. Visually inspect all air intake hoses and connections for cracks, splits, or loose fittings.
  2. Tighten any loose clamps and replace damaged hoses.
  3. Ensure that the air filter is clean and properly installed.

3. Check Fuel Pressure

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition key to the "ON" position without starting the engine and observe the pressure reading.
  3. Compare the reading to the manufacturer’s specifications (typically 30-40 psi for this model).
  4. If low, inspect the fuel pump and filter for issues, and replace if necessary.

4. Clean MAF Sensor

• Sub-steps:
  1. Disconnect the electrical connector from the MAF sensor.
  2. Remove the sensor from the air intake duct using the appropriate socket.
  3. Spray MAF cleaner onto the sensor elements and allow them to dry completely.
  4. Reinstall the MAF sensor and reconnect the electrical connector.

5. Inspect Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Use a multimeter to check for proper voltage readings (typically between 0.1 to 0.9 volts for a functioning sensor).
  3. If readings are out of spec, replace the faulty oxygen sensor.

6. Inspect Fuel Injectors

• Sub-steps:
  1. Visually inspect fuel injectors for leaks or clogs.
  2. If necessary, remove the injectors and clean them using an ultrasonic cleaner.
  3. Reinstall the injectors and check for proper sealing.