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

Solution

1. Preparation

• Gather tools and parts required.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool down before starting work.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses for cracks or disconnection.
  2. Use a smoke machine or propane torch (without flame) to detect leaks.
  3. Replace any damaged hoses or gaskets found during inspection.
• Tools Required: Smoke machine, propane torch, hose clamp pliers.

3. Clean or Replace the MAF Sensor

• Sub-steps:
  1. Disconnect the MAF sensor connector.
  2. Remove the MAF sensor from the air intake duct.
  3. Clean the sensor using MAF cleaner spray, ensuring not to touch the sensing element.
  4. Let it dry completely before reinstalling.
  5. If cleaning does not resolve the code, replace the MAF sensor.
• Tools Required: Screwdriver set, MAF cleaner spray.

4. Check and Repair 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) to check fuel pressure.
  3. Compare the reading with the manufacturer's specifications (usually around 30-45 psi).
  4. If the pressure is low, inspect the fuel pump and replace the fuel filter if necessary.
• Tools Required: Fuel pressure gauge, socket set.

5. Inspect and Clean Throttle Body

• Sub-steps:
  1. Remove the air intake duct connected to the throttle body.
  2. Use throttle body cleaner to clean the throttle plate and intake passages.
  3. Ensure the throttle plate moves freely and is not obstructed.
  4. Reinstall the air duct securely.
• Tools Required: Throttle body cleaner, socket set.

6. Reconnect Battery and Clear Codes

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0171 code.
  3. Start the engine and allow it to reach operating temperature.
• Tools Required: OBD-II scanner.