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

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Ensure the vehicle is parked on a level surface and the engine is cool.

2. Inspect Air Intake System

• Tools Required: Visual inspection tools
• Inspect all vacuum hoses for cracks or disconnections. Replace any damaged hoses.
• Check the intake manifold gasket for leaks and replace if necessary.

3. Clean the Mass Air Flow (MAF) Sensor

• Tools Required: MAF sensor cleaner, screwdriver
• Remove the MAF sensor from the air intake duct.
• Spray the MAF sensor with MAF cleaner, avoiding contact with the sensor's wires.
• Allow the sensor to dry completely before reinstalling.

4. Check Fuel Pressure

• Tools Required: Fuel pressure gauge, appropriate adapters
• 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 the pressure reading against the manufacturer's specifications.
• If the pressure is low, inspect the fuel pump and fuel filter for issues.

5. Inspect Fuel Injectors

• Tools Required: Injector cleaning kit, multimeter
• Visually inspect fuel injectors for leaks or clogs.
• Use an injector cleaning kit to clean the injectors if necessary.
• Test each injector's resistance with a multimeter to ensure they are within specifications.

6. Reassemble and Test

• Reinstall any removed components and ensure all connections are secure.
• Reconnect the negative battery terminal.
• Start the engine and allow it to idle. Monitor for any warning lights or abnormal running conditions.