how to fix P0174 code in my Toyota Highlander Third Generation (2014-2019)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to avoid any electrical shorts during repairs.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  • Visually inspect vacuum hoses for cracks or disconnections.
  • Use a smoke machine or carburetor cleaner around hoses and gaskets to identify leaks.
  • Replace any damaged hoses or gaskets found during the inspection.

3. Check Fuel Pressure

• Sub-steps:
  • Locate the fuel rail and connect the fuel pressure gauge.
  • Turn the ignition to the "ON" position (without starting the engine) to measure the fuel pressure.
  • Compare the reading to the manufacturer's specifications (typically around 50-60 psi).
  • If pressure is low, inspect the fuel pump and fuel filter for faults and replace as necessary.

4. Inspect and Clean MAF Sensor

• Sub-steps:
  • Locate the MAF sensor in the air intake system.
  • Disconnect the electrical connector and remove the sensor from the housing.
  • Use MAF sensor cleaner to gently clean the sensor elements.
  • Reinstall the sensor and reconnect the electrical connector.

5. Inspect Fuel Injectors

• Sub-steps:
  • Remove the engine cover to access the fuel injectors.
  • Check for proper electrical connections to each injector.
  • Perform a resistance test on each injector with a multimeter to ensure they are functioning properly (typically around 12-16 ohms).
  • Replace any malfunctioning injectors.