how to fix P0174 code in Toyota Highlander Fourth Generation (2020-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Vacuum gauge, hose clamps, basic hand tools
• Sub-steps:
  1. Use a vacuum gauge to test for leaks in the vacuum system.
  2. Inspect all vacuum hoses connected to the intake manifold; replace any damaged hoses.
  3. Tighten any loose hose clamps.

3. Clean or Replace MAF Sensor

• Tools Required: MAF cleaner, screwdriver
• Sub-steps:
  1. Locate the MAF sensor in the intake air duct.
  2. Disconnect the electrical connector from the MAF sensor.
  3. Remove the MAF sensor using the appropriate screwdriver.
  4. Clean the sensor with MAF cleaner and allow it to dry, or replace it if damaged.
  5. Reinstall the MAF sensor and reconnect the electrical connector.

4. Inspect and Replace Fuel Filter

• Tools Required: Fuel line removal tool, wrench set
• Sub-steps:
  1. Relieve the fuel system pressure by removing the fuel pump fuse and running the engine until it stalls.
  2. Disconnect the fuel lines from the fuel filter using the fuel line removal tool.
  3. Remove the old fuel filter and install the new one, ensuring the flow direction is correct.
  4. Reconnect the fuel lines securely.

5. Replace Intake Manifold Gasket (if necessary)

• Tools Required: Socket set, gasket scraper, torque wrench
• Sub-steps:
  1. Disconnect any components obstructing access to the intake manifold.
  2. Remove the intake manifold bolts using the socket set.
  3. Carefully lift the intake manifold off and scrape off the old gasket material.
  4. Place a new gasket onto the engine.
  5. Reinstall the intake manifold and torque the bolts to the manufacturer’s specifications.