how to fix P0174 code in Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Ensure the engine is cool before starting work.

2. Inspect and Repair Air Intake System

• Inspect Hoses and Gaskets:
  • Visually examine all vacuum hoses and gaskets for cracks or disconnections.
  • Replace any damaged hoses or gaskets.
• Reconnect any loose connections: Ensure all clamps and connections are secure.

3. Clean or Replace MAF Sensor

• Remove MAF Sensor:
  • Use a Torx or Phillips screwdriver to remove the MAF sensor from the air intake.
• Clean with MAF Cleaner:
  • Spray MAF cleaner onto the sensor elements and allow it to dry completely before reinstallation.
• Reinstall MAF Sensor:
  • Carefully reinstall the sensor, ensuring it is secured properly.

4. Inspect and Test Fuel System

• Check Fuel Pressure:
  • Connect a fuel pressure gauge to the fuel rail and turn on the ignition without starting the engine; check that pressure meets specifications (usually around 50-60 psi).
• Replace Fuel Filter (if applicable):
  • If fuel pressure is low, replace the fuel filter according to manufacturer's guidelines.
• Test Fuel Injectors:
  • Use a noid light to ensure the injectors are receiving the correct signals. Replace any faulty injectors.

5. Clean Throttle Body

• Remove Throttle Body:
  • Disconnect the throttle body from the intake manifold by removing the bolts using a socket set.
• Clean with Throttle Body Cleaner:
  • Use throttle body cleaner and a soft cloth to clean the inside of the throttle body. Avoid damaging the throttle plate.
• Reinstall Throttle Body:
  • Reattach the throttle body and torque the bolts to the manufacturer's specifications.