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

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.

Tools Required:

• OBD-II scanner
• Fuel pressure gauge
• Socket set
• Screwdrivers
• Multimeter
• Vacuum gauge (optional)

2. Inspect and Repair Air Intake System

• Remove the air intake duct and inspect for cracks or loose connections.
• Check the intake manifold for any leaks using a smoke test or carb cleaner spray.
• Replace any damaged hoses or components.

3. Clean or Replace MAF Sensor

• Disconnect the MAF sensor connector.
• Remove the MAF sensor from the intake duct.
• Clean the sensor with MAF cleaner; do not touch the sensor element.
• If cleaning does not resolve the issue, replace the MAF sensor.

4. Check and Adjust Fuel Pressure

• Connect the fuel pressure gauge to the fuel rail.
• Turn the ignition to the "ON" position without starting the engine and check the pressure.
• Compare the reading to manufacturer specifications (usually between 50-60 psi for most Toyotas).
• If pressure is low, inspect the fuel pump, filter, and relay. Replace as necessary.

5. Inspect Fuel Injectors

• Remove the fuel rail to access the injectors.
• Inspect the injectors for clogs; clean or replace if necessary.
• Ensure all injector connectors are secure.

6. Final Checks

• Reassemble any components removed during repairs.
• Reconnect the battery.
• Start the engine and monitor for any leaks or persistent codes.