how to fix P0171 lean code on Toyota RAV4 Fifth Generation (2019-present)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to avoid electrical shorts.
• Allow the engine to cool down.

2. Inspect and Repair Air Intake System

• Tools Required: Screwdriver set, hose clamps, vacuum gauge.
• Sub-steps:
  1. Visually inspect the air intake hoses for any signs of wear or damage.
  2. Use a vacuum gauge to check for leaks in the intake manifold and vacuum lines.
  3. Tighten any loose connections or replace damaged hoses.

3. Clean or Replace MAF Sensor

• Tools Required: MAF cleaner or isopropyl alcohol, soft brush.
• Sub-steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector and unscrew the sensor from the duct.
  3. Spray the sensor with MAF cleaner and let it dry completely.
  4. Reinstall the sensor and reconnect the electrical connector.

4. Check and Adjust Fuel Pressure

• Tools Required: Fuel pressure gauge.
• Sub-steps:
  1. Locate the fuel pressure test port on the fuel rail.
  2. Connect the fuel pressure gauge to the test port.
  3. Start the engine and monitor the fuel pressure reading; it should be within manufacturer specifications (typically around 40-50 PSI).
  4. If pressure is low, inspect the fuel pump and fuel filter for issues.

5. Inspect and Test Fuel Injectors

• Tools Required: Multimeter, fuel injector cleaner.
• Sub-steps:
  1. Disconnect the electrical connectors from the fuel injectors.
  2. Use a multimeter to check the resistance of each injector (should be around 12-16 ohms).
  3. If any injectors are faulty, replace them.
  4. Clean the injectors using a fuel injector cleaning kit if necessary.

6. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0171 code and any other stored codes.