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

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the battery to ensure safety during repairs.

2. Inspect and Repair Air Intake System

• Inspect Air Filter: Check and replace if dirty.
• Inspect Hoses: Look for cracks or loose connections in vacuum and intake hoses and replace as necessary.
• Tighten Clamps: Ensure all clamps securing hoses are tight.

3. Check and Clean MAF Sensor

• Remove MAF Sensor: Detach the electrical connector and unscrew the MAF sensor from the air intake.
• Clean with Cleaner: Use MAF cleaner spray to clean the sensor carefully. Allow it to dry completely.
• Reinstall MAF Sensor: Securely attach the MAF sensor back onto the intake.

4. Inspect and Test Fuel System

• Check Fuel Pressure: Connect a fuel pressure gauge to the fuel rail and check if the pressure meets specifications (usually around 50-60 psi).
• Replace Fuel Filter: If the filter is clogged, replace it.
• Inspect Fuel Injectors: Remove injectors and clean or replace if they are clogged.

5. Throttle Body Cleaning

• Remove Throttle Body: Disconnect the throttle body from the intake manifold.
• Clean Throttle Body: Use throttle body cleaner and a soft brush to remove carbon buildup.
• Reinstall Throttle Body: Reattach securely to the intake.

6. Final Checks

• Reconnect Battery: After all repairs are complete, reconnect the battery.
• Clear Codes: Use the OBD-II scanner to clear the P0171 code.