how to fix P0174 code on Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool if previously running.

2. Inspect and Repair Air Intake System

• Sub-steps:
  1. Remove engine cover (if applicable) using a socket set.
  2. Inspect the air intake hose for cracks or looseness; replace if damaged.
  3. Tighten or replace any loose clamps.
  4. Check the intake manifold gasket for signs of wear or leaks; replace if necessary.

3. Clean or Replace Mass Airflow Sensor

• Tools Required: MAF cleaner, screwdriver
• Sub-steps:
  1. Locate the MAF sensor along the air intake duct.
  2. Disconnect the electrical connector and remove the MAF sensor using a screwdriver.
  3. Clean the sensor with MAF cleaner and allow it to dry completely.
  4. Reinstall the sensor and reconnect the electrical connector.

4. Inspect Fuel System

• Sub-steps:
  1. Use a fuel pressure gauge to check fuel pressure at the fuel rail.
  2. If pressure is low, inspect the fuel pump and replace the fuel filter if clogged.
  3. Ensure proper wiring and connections to the fuel injectors.

5. Inspect and Replace Vacuum Lines

• Sub-steps:
  1. Visually inspect all vacuum lines for cracks or disconnections.
  2. Replace any damaged vacuum hoses.
  3. Check that all connections are secure and tight.