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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to ensure safety while working on the electrical systems.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Vacuum gauge, hose clamp pliers
• Sub-steps:
  1. Use a vacuum gauge to check for leaks in the intake manifold and vacuum hoses.
  2. If leaks are found, replace the damaged hoses or gaskets.
  3. Reconnect any loose connections securely.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, Torx screwdriver
• Sub-steps:
  1. Locate the MAF sensor on the intake duct.
  2. Disconnect the electrical connector and remove the sensor using the Torx screwdriver.
  3. Clean the MAF sensor with MAF cleaner. Allow it to dry completely.
  4. If damaged, replace the MAF sensor with a new one.
  5. Reinstall and reconnect the sensor.

4. Check and Repair Fuel System

• Tools Required: Fuel pressure gauge, wrench set
• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "ON" position (do not start the engine) and check the pressure reading.
  3. Compare the reading to the manufacturer's specifications. If the pressure is low, inspect the fuel pump and filter.
  4. Replace any faulty components as needed.

5. Inspect Fuel Injectors

• Tools Required: Fuel injector cleaner kit, safety glasses
• Sub-steps:
  1. Remove the fuel injectors from the fuel rail.
  2. Clean the injectors using a fuel injector cleaning kit.
  3. Check for any signs of wear or damage; replace any defective injectors.
  4. Reinstall the cleaned or new injectors.

6. Check Oxygen Sensors

• Tools Required: Multimeter
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Disconnect the electrical connectors from the sensors.
  3. Use a multimeter to test the sensor voltage and resistance according to manufacturer specifications.
  4. Replace any malfunctioning sensors with new ones.