how to fix the P0171 code in my Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the vehicle's battery to ensure safety while working on electrical components.

2. Inspect and Repair Air Intake System

• Tools Required: Socket set, screwdrivers, vacuum gauge.
• Inspect hoses and clamps for any signs of wear or damage.
• Replace any damaged hoses or tighten loose connections.
• Check the air filter and replace it if it’s clogged or dirty.

3. Fuel Pressure Check

• Tools Required: Fuel pressure gauge.
• Connect the fuel pressure gauge to the fuel rail.
• Turn the ignition on (do not start the engine) and check the fuel pressure. It should be within manufacturer specifications (typically around 50-60 psi for many vehicles).
• If the pressure is low, inspect the fuel pump, fuel filter, and fuel injectors for functionality.

4. Clean or Replace MAF Sensor

• Tools Required: MAF cleaner (specific cleaner recommended), torx or socket set.
• Disconnect the MAF sensor electrical connector and remove the sensor from the air intake.
• Spray the MAF cleaner onto the sensor element (do not touch it with fingers).
• Allow it to dry completely before reinstalling. If the sensor is damaged, replace it with a new one.

5. Inspect Oxygen Sensors and Exhaust

• Tools Required: O2 sensor socket or wrench.
• Locate and inspect the upstream oxygen sensor for any signs of damage or contamination.
• If faulty, replace the oxygen sensor.
• Check for any exhaust leaks in the manifold and pipes; repair as necessary.

6. Reconnect Battery and Clear Codes

• Reconnect the battery once all repairs are completed.
• Use the OBD-II scanner to clear the P0171 code and perform a test drive to ensure the issue is resolved.