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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool down before starting work.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Vacuum gauge, hose clamps
• Inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
• Replace any damaged hoses and secure them with hose clamps.
• Check the intake manifold gasket for leaks and replace if necessary.

3. Clean or Replace Mass Airflow Sensor

• Tools Required: MAF cleaner, small screwdriver
• Disconnect the MAF sensor connector.
• Remove the MAF sensor from the intake tube using a screwdriver.
• Spray MAF cleaner on the sensor element and let it dry completely.
• Reinstall the sensor and reconnect the electrical connector.

4. Test Fuel Pressure

• Tools Required: Fuel pressure gauge
• Locate the fuel rail test port and connect the fuel pressure gauge.
• Turn the ignition key to the "ON" position (do not start) to check the fuel pressure.
• Compare the reading to the manufacturer’s specifications; replace the fuel pump if the pressure is low.

5. Inspect and Clean Fuel Injectors

• Tools Required: Fuel injector cleaner, cleaning kit
• Remove the fuel injectors from the fuel rail.
• Use a fuel injector cleaning kit to clean the injectors according to the manufacturer’s instructions.
• Inspect the injector O-rings for wear and replace if necessary before reinstalling.

6. Verify Oxygen Sensor Functionality

• Tools Required: Multimeter
• Disconnect the O2 sensor connector.
• Use a multimeter to test the sensor's voltage output while the engine is running (should fluctuate between 0.1 to 0.9 volts).
• Replace the oxygen sensor if it does not meet specifications.