my Toyota RAV4 XA50 (2019-2024) has a P0171 code, what does that mean?

Solution

1. Preparation

• Gather tools and parts needed.
• Disconnect the battery to ensure safety.
• Allow the engine to cool before starting work.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum lines and intake ducts for cracks or disconnections.
  2. Use a smoke machine or propane torch (without igniting) to detect leaks around the intake manifold.
  3. Replace any damaged hoses or gaskets.
• Tools Required: Smoke machine or propane torch, pliers.

3. Check and Clean the MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor, typically found between the air filter and the throttle body.
  2. Disconnect the electrical connector and remove the sensor from its housing.
  3. Clean the MAF sensor using MAF cleaner spray and a lint-free cloth. Avoid touching the sensor element.
  4. Reinstall the MAF sensor and reconnect the electrical connector.
• Tools Required: MAF cleaner, lint-free cloth, screwdriver.

4. Test and Replace Fuel Pump (if needed)

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "ON" position without starting the engine and check the pressure reading.
  3. If the pressure is below specifications, replace the fuel pump.
  4. Remove the old fuel pump from the fuel tank as per the manufacturer’s service manual.
  5. Install the new fuel pump and ensure all connections are secure.
• Tools Required: Fuel pressure gauge, socket set, service manual.

5. Inspect and Replace Oxygen Sensors (if needed)

• Sub-steps:
  1. Locate the upstream oxygen sensor (pre-catalytic converter).
  2. Disconnect the electrical connector and unscrew the sensor using an O2 sensor socket.
  3. Install the new oxygen sensor and reconnect the electrical connector.
• Tools Required: O2 sensor socket, wrench set.