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

Solution

1. Preparation

• Gather required tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Repair Vacuum Leaks

• Inspect all vacuum hoses:
  • Look for cracks or disconnections.
  • Replace any damaged hoses.
• Check intake manifold gaskets:
  • Inspect for leaks using a smoke machine or carb cleaner.
  • Replace gaskets if leaks are present.

3. Clean or Replace MAF Sensor

• Remove the MAF sensor:
  • Unscrew the sensor from the air intake assembly.
  • Use a Torx or Phillips screwdriver as applicable.
• Clean the MAF sensor:
  • Spray MAF sensor cleaner on the sensor elements.
  • Let it dry completely before reinstalling.
• If damaged, replace the sensor:
  • Install the new MAF sensor and secure it with screws.

4. Check Fuel System

• Test fuel pressure:
  • Connect a fuel pressure gauge to the fuel rail.
  • Start the engine and check the fuel pressure against manufacturer specifications (typically 50-60 psi).
  • If low, inspect the fuel pump and filter for issues.
• Inspect fuel injectors:
  • Remove the fuel rail assembly.
  • Check for clogs or leaks and replace as necessary.

5. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the code and reset the system.