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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool before starting work.

2. Inspect and Repair Air Intake System

• Tools Required: Socket set, screwdrivers.
• Check all air intake hoses and connections for cracks or loose fittings.
• Replace any damaged hoses and ensure all connections are secure.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, torx screwdriver.
• Remove the MAF sensor from the air intake duct.
• Clean the sensor with MAF cleaner and allow it to dry completely before reinstalling.
• If the sensor is damaged, replace it with a new one.

4. Check Fuel Pressure

• Tools Required: Fuel pressure gauge.
• Connect the fuel pressure gauge to the fuel rail test port.
• Turn the ignition to the "ON" position without starting the engine and check the pressure reading.
• If the pressure is below manufacturer's specifications, inspect the fuel pump and fuel filter for issues.

5. Inspect and Repair Fuel Injectors

• Tools Required: Injector O-ring kit, cleaning kit (if necessary).
• Remove the fuel rail to access the injectors.
• Inspect the injectors for clogs or leaks; clean or replace as needed.
• Ensure that the O-rings are in good condition and replace them if necessary.

6. Verify Oxygen Sensor Functionality

• Tools Required: Multimeter.
• Test the voltage output of the oxygen sensors at operating temperature.
• Replace any malfunctioning oxygen sensors with new ones.