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

Solution

1. Preparation

• Gather all necessary tools and parts before starting the repair.
• Ensure the vehicle is parked on a flat surface, and the engine is cool.
• Disconnect the negative battery cable to prevent electrical shorts.

2. Inspect and Repair Air Intake System

• Inspect Hoses:

  • Check all hoses connected to the air intake for cracks or disconnections. Replace any damaged hoses.

• Inspect MAF Sensor:

  • Carefully remove the MAF sensor from the air intake duct.
  • Use MAF cleaner to clean the sensor elements thoroughly and allow it to dry before reinstalling.

3. Fuel System Check

• Test Fuel Pressure:

  • Connect the fuel pressure gauge to the fuel rail test port.
  • Turn the ignition to the "ON" position (do not start the engine) and check fuel pressure; it should meet manufacturer specifications (typically 50-60 psi).
  • If pressure is low, inspect the fuel pump, filter, and relay.

• Inspect Fuel Injectors:

  • Remove the fuel rail to access the injectors.
  • Inspect each injector for clogs; use a fuel injector cleaner if necessary.
  • Replace any faulty injectors if clogs cannot be cleared.

4. Check for Vacuum Leaks

• Inspect all vacuum lines for wear and tear, replacing any damaged lines.
• Use smoke testing to identify any hidden vacuum leaks that may not be visible.

5. Reassemble and Clear Codes

• Reinstall all components removed during inspection.
• Reconnect the negative battery cable.
• Clear the P0174 code using the OBD-II scanner and start the engine to monitor for any reoccurrence.