how to fix P0171 code in a Toyota RAV4 Fifth Generation (2019-present)

Solution

1. Preparation

• Tools Required: OBD-II scanner, fuel pressure gauge, socket set, screwdriver set, multimeter, cleaning supplies (MAF cleaner, throttle body cleaner).
• Disconnect the vehicle battery to prevent electrical shorts.
• Allow the engine to cool before starting work.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
  2. Use a smoke machine or carburetor cleaner to identify leaks.
  3. Replace any damaged hoses or gaskets as needed.

3. Clean the MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor along the air intake duct.
  2. Disconnect the electrical connector and the intake duct.
  3. Spray MAF cleaner on the sensor elements without touching them.
  4. Allow the sensor to dry completely before reinstallation.

4. Check and Clean Throttle Body

• Sub-steps:
  1. Remove the air intake duct connected to the throttle body.
  2. Use a throttle body cleaner and a soft cloth to clean the throttle plate and surrounding areas.
  3. Inspect for any carbon buildup that may affect throttle operation.
  4. Reassemble and reconnect the intake duct securely.

5. Test Fuel Pressure

• Sub-steps:
  1. Locate the fuel rail and connect the fuel pressure gauge.
  2. Turn the ignition to the "ON" position without starting the engine to check the static fuel pressure.
  3. Compare the reading to the manufacturer's specifications (usually around 50-60 PSI for RAV4).
  4. If the pressure is low, inspect the fuel pump and filter for issues.

6. Inspect Fuel Injectors

• Sub-steps:
  1. Disconnect the electrical connectors from the fuel injectors.
  2. Check the resistance using a multimeter to ensure they are within specifications.
  3. Clean the injectors using an appropriate injector cleaner or replace them if faulty.