how to fix the P0174 code on my Toyota Highlander Third Generation (2014-2019)?

Solution

1. Preparation

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

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses for cracks or disconnections.
  2. Use a smoke machine or carburetor cleaner to identify leaks around the intake manifold and vacuum lines.
  3. Replace any faulty hoses or gaskets as needed.
• Tools Required: Smoke machine, carburetor cleaner, pliers.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Disconnect the MAF sensor electrical connector.
  2. Remove the MAF sensor from the air intake duct.
  3. Clean the sensor with MAF cleaner and let it dry completely, or replace it if damaged.
  4. Reinstall the MAF sensor and reconnect the electrical connector.
• Tools Required: Torx or socket set, MAF cleaner.

4. Check Fuel Pressure

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition to the "ON" position without starting the engine and check the pressure reading.
  3. Compare the reading with manufacturer specifications; replace the fuel pump if pressure is low.
• Tools Required: Fuel pressure gauge.

5. Inspect Fuel Injectors

• Sub-steps:
  1. Remove the engine cover if necessary to access fuel injectors.
  2. Check for fuel leaks around the injectors and listen for any unusual sounds indicating malfunctions.
  3. Clean or replace clogged injectors.
• Tools Required: Socket set, injector cleaning kit or replacement injectors.