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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool down if it has been running.

2. Inspect and Repair Air Intake System

• Sub-steps:
  1. Visually inspect the air intake hoses for any signs of damage or leaks.
  2. Replace any damaged hoses or clamps.
  3. Clean or replace the air filter if it is dirty or clogged.

3. Check and Clean MAF Sensor

• Sub-steps:
  1. Disconnect the MAF sensor connector.
  2. Remove the MAF sensor from the air intake duct.
  3. Use MAF sensor cleaner to clean the sensor elements carefully.
  4. Reinstall the MAF sensor and reconnect the electrical connector.

4. Inspect Fuel Delivery System

• Sub-steps:
  1. Check fuel pressure at the fuel rail using a fuel pressure gauge; it should meet manufacturer specifications (usually around 50-60 psi).
  2. Replace the fuel filter if it has not been changed recently.
  3. Inspect fuel injectors for proper operation and clean them if necessary.

5. Check and Replace Oxygen Sensors (if necessary)

• Sub-steps:
  1. Disconnect the electrical connectors from the O2 sensors.
  2. Remove O2 sensors from the exhaust system using an O2 sensor socket.
  3. Install new O2 sensors and reconnect the electrical connectors.