what does it mean if my Toyota Highlander XU70 (2020-Present) has a P0171 code?

Solution

1. Preparation

• Gather tools and safety equipment.
• Disconnect the negative battery terminal.
• Allow the engine to cool down completely.

2. Inspect and Repair Air Leaks

• Tools Required: Vacuum gauge, hose clamps, screwdriver.
• Visually inspect all hoses connected to the intake manifold for cracks or loose connections.
• Use a vacuum gauge to check for leaks and tighten or replace any faulty hoses.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, screwdriver.
• Remove the MAF sensor from the intake manifold.
• Clean the sensor with MAF cleaner (do not use other cleaners).
• Reinstall the cleaned or new MAF sensor.

4. Check Fuel System Components

• Tools Required: Fuel pressure gauge, wrench set.
• Connect the fuel pressure gauge to the fuel rail and turn the ignition to the "ON" position (do not start).
• Check if the fuel pressure is within the specified range (consult the service manual).
• Replace the fuel filter if pressure is below specifications.

5. Inspect Fuel Injectors

• Tools Required: Socket set, multimeter (if testing injector resistance).
• Remove the fuel rail to access the injectors.
• Inspect each injector for clogs or leaks and test their electrical connections with a multimeter.
• Replace any faulty injectors.

6. Clear Engine Codes

• Tools Required: OBD-II scanner.
• After repairs, reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0171 code from the vehicle’s computer.