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

Solution

1. Preparation

• Gather the necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool if it has been running.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses connected to the intake manifold and throttle body for cracks or disconnection.
  2. Use a smoke machine or carburetor cleaner around suspected areas to detect leaks.
  3. Replace any damaged hoses or gaskets found during inspection.

Tools Required: Vacuum hose inspection tools, smoke machine, carburetor cleaner.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector and remove the sensor.
  3. Clean the MAF sensor with MAF cleaner spray and a soft brush; let it dry completely.
  4. If damaged, replace the MAF sensor with a new one.

Tools Required: MAF cleaner spray, soft brush, screwdriver set.

4. Check and Adjust Fuel Pressure

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition to the ON position (do not start the engine) to check the fuel pressure.
  3. If the pressure is below specifications (typically around 43-50 psi), inspect the fuel pump and fuel filter for issues.
  4. Replace the fuel filter or fuel pump as necessary.

Tools Required: Fuel pressure gauge, wrench set.

5. Inspect and Replace Fuel Injectors

• Sub-steps:
  1. Remove the engine cover and access the fuel rail.
  2. Disconnect the fuel injector connectors and remove the fuel rail bolts.
  3. Carefully pull the fuel rail and injectors out, inspecting them for clogs or leaks.
  4. Clean the injectors using a fuel injector cleaner kit or replace them if necessary.

Tools Required: Socket set, fuel injector cleaner kit.

6. Reassemble and Reconnect

• Sub-steps:
  1. Reinstall the fuel rail and injectors, ensuring proper seating.
  2. Reconnect all electrical connectors and vacuum hoses.
  3. Reattach the negative battery terminal.

Tools Required: Socket set, pliers.