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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative terminal of the battery.
• Ensure the engine is cool before starting work.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses connected to the intake manifold.
  2. Use a smoke machine or carburetor cleaner to check for leaks; listen for hissing sounds.
  3. Replace any damaged or cracked hoses.

3. Check and Clean MAF Sensor

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

4. Test Fuel Pressure

• Sub-steps:
  1. Locate the fuel pressure test port on the fuel rail.
  2. Attach a fuel pressure gauge to the test port.
  3. Turn the ignition to the "ON" position (do not start) and read the fuel pressure.
  4. Compare the reading to the manufacturer’s specification (typically around 50-60 psi for this model).
  5. If the pressure is low, check the fuel pump and fuel filter for issues.

5. Inspect Fuel Injectors

• Sub-steps:
  1. Remove the engine cover to access the fuel rail and injectors.
  2. Disconnect the fuel injector electrical connectors.
  3. Use a multimeter to test the resistance of each injector to ensure they are functioning properly.
  4. If injectors are clogged, consider using a fuel injector cleaning kit or replace them if necessary.

6. Reassemble and Reset

• Sub-steps:
  1. Reconnect all components and ensure all connections are secure.
  2. Reconnect the negative battery terminal.
  3. Start the engine and allow it to idle for a few minutes.