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

Solution

1. Preparation

• Tools Required: OBD-II scanner, vacuum gauge, fuel pressure gauge, MAF cleaner, socket set, torque wrench.
• Gather necessary parts based on diagnostics.
• Disconnect the battery to ensure safety.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses and connections for cracks or disconnections.
  2. Use a smoke machine or spray soapy water to identify leaks.
  3. Replace any damaged hoses or gaskets found during inspection.
  4. Reconnect any loose connections securely.

3. Check and Clean the MAF Sensor

• Sub-steps:
  1. Remove the MAF sensor from the air intake duct.
  2. Spray MAF cleaner onto the sensor elements; do not touch them with your fingers.
  3. Allow it to dry completely before reinstalling.
  4. Reinstall the MAF sensor, ensuring all connections are secure.

4. Inspect and Test the Fuel System

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the ON position (do not start) and check the fuel pressure; it should meet manufacturer specifications (typically around 50-60 psi).
  3. If pressure is low, check the fuel pump and filter for clogs or malfunctions; replace as necessary.
  4. Test the fuel injectors by checking for proper operation; replace any faulty injectors.

5. Reset the ECM

• Sub-steps:
  1. Reconnect the battery terminal.
  2. Use the OBD-II scanner to clear the P0171 code from the ECM.
  3. Start the engine and let it idle for a few minutes.