how to fix P0171 code in my Toyota RAV4 Fourth Generation (2013-2018)

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Ensure you have safety glasses and gloves.

2. Inspect and Repair Vacuum Leaks

• Visually inspect all vacuum hoses connected to the intake manifold.
• Use a smoke machine to detect any hidden leaks.
• Replace any damaged hoses or gaskets found during inspection.

3. Check and Clean MAF Sensor

• Remove the MAF sensor from the air intake housing using a Torx or Phillips screwdriver.
• Spray MAF cleaner onto the sensor element to remove dirt and debris without touching it.
• Allow the sensor to dry completely before reinstalling.

4. Test and Adjust Fuel Pressure

• Connect a fuel pressure gauge to the fuel rail's Schrader valve.
• Turn the ignition to the ON position (do not start the engine) and check the pressure reading.
• If the pressure is below specifications, check the fuel pump and filter for functionality.
• Replace the fuel filter if clogged and test the fuel pump operation.

5. Inspect and Clean Fuel Injectors

• Remove the fuel rail from the engine, being careful to catch any fuel spills.
• Clean the fuel injectors using an ultrasonic cleaner or replace them if they are faulty.
• Reinstall the fuel rail and ensure all connections are secure.

6. Replace Oxygen Sensor (if necessary)

• If the upstream oxygen sensor is faulty, locate it in the exhaust manifold or pipe.
• Use an O2 sensor socket to remove the old sensor.
• Install the new sensor, ensuring it is tightened to the manufacturer’s specifications (usually around 30 Nm or 22 lb-ft).
• Reconnect the electrical connector.