how to fix P0171 code on Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to ensure safety during electrical work.

2. Inspect and Repair Air Intake System

• Tools Required: Screwdriver set, vacuum gauge
• Inspect all vacuum lines for cracks or disconnections.
• Tighten or replace any loose or damaged hoses.
• Check the intake manifold for any signs of leaks and reseal with appropriate gasket material if necessary.

3. Fuel System Check

• Tools Required: Fuel pressure gauge
• Connect the fuel pressure gauge to the fuel rail.
• Turn the ignition to the "ON" position without starting the engine.
• Record the fuel pressure reading; it should be within manufacturer specifications (usually around 50-60 psi for most Toyota models).
• If pressure is low, check the fuel pump and filter for blockages or failures.

4. Clean or Replace MAF Sensor

• Tools Required: MAF cleaner, Torx screwdriver
• Locate the MAF sensor in the air intake duct.
• Remove the MAF sensor carefully.
• Clean the sensor with MAF cleaner, ensuring no residue is left.
• If the sensor is damaged, replace it with a new one.

5. Inspect Fuel Injectors

• Tools Required: Fuel injector cleaning kit (if needed)
• Remove the engine cover to access the fuel injectors.
• Inspect for signs of leakage or blockage.
• Use a fuel injector cleaning kit if necessary, or replace faulty injectors.

6. Reassemble and Test

• Reconnect all components, ensuring no hoses are loose or disconnected.
• Reconnect the battery.
• Start the engine and let it idle to check for any leaks or abnormal sounds.