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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery.
• Ensure the vehicle is parked on a level surface and the engine is cool.

2. Inspect and Repair Air Intake System

• Tools Required: Socket set, screwdriver set, vacuum gauge.
• Steps:
  1. Remove the engine cover if necessary.
  2. Inspect the air intake duct for any cracks or loose fittings and replace as needed.
  3. Check the air filter and replace it if it is dirty or clogged.
  4. Reinstall any removed components and reconnect the battery.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, wrench set.
• Steps:
  1. Locate the MAF sensor on the air intake duct.
  2. Disconnect the electrical connector and remove the sensor.
  3. Clean the MAF sensor with MAF cleaner spray and allow it to dry completely.
  4. If the sensor is damaged, replace it with a new one.
  5. Reinstall the sensor and reconnect the electrical connector.

4. Check and Adjust Fuel Delivery

• Tools Required: Fuel pressure gauge, socket set.
• Steps:
  1. Connect the fuel pressure gauge to the fuel rail.
  2. Turn the ignition key to the "ON" position (do not start the engine) and check the fuel pressure.
  3. Compare the reading to the manufacturer's specifications. If it is low, inspect the fuel pump, fuel filter, and fuel injectors.
  4. Replace any faulty components.

5. Repair Vacuum Leaks

• Tools Required: Smoke machine or propane torch (with caution), wrench set.
• Steps:
  1. Perform a smoke test to identify vacuum leaks around the intake manifold and hoses.
  2. If leaks are detected, replace or repair the affected hoses and gaskets.
  3. Recheck the integrity of the intake manifold and reseal if necessary.