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 ensure safety while working on electrical components.

2. Inspect and Repair Air Intake System

• Sub-steps:

  1. Visually inspect all air intake hoses and clamps for cracks or disconnections.
  2. Tighten any loose clamps and replace damaged hoses.
  3. Check the intake manifold for any vacuum leaks.

• Tools Required:

  • Socket set
  • Screwdriver set

3. Clean or Replace MAF Sensor

• Sub-steps:

  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector and remove the MAF sensor.
  3. Clean the sensor with MAF cleaner or replace it if damaged.
  4. Reinstall the sensor and reconnect the electrical connector.

• Tools Required:

  • Torx or Phillips screwdriver
  • MAF cleaner

4. Check Fuel Pressure

• Sub-steps:

  1. Connect the fuel pressure gauge to the fuel rail.
  2. Turn the ignition key to the ON position without starting the engine, and check the pressure reading.
  3. Compare the reading to the manufacturer's specifications (typically between 40-50 psi).
  4. If the pressure is low, inspect the fuel pump and filter, replacing them as necessary.

• Tools Required:

  • Fuel pressure gauge
  • Wrench set

5. Inspect and Test Oxygen Sensors

• Sub-steps:

  1. Locate the upstream and downstream oxygen sensors.
  2. Disconnect the sensors and check for corrosion or damage.
  3. Use a multimeter to test the sensors for proper voltage output.
  4. Replace any faulty oxygen sensors.

• Tools Required:

  • Multimeter
  • O2 sensor socket