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 ensure safety.

2. Inspect Air Intake System

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Visually inspect the air intake hoses for cracks or disconnections.
  3. If any leaks are found, replace the affected hoses.
• Tools Required: Screwdriver, inspection mirror.

3. Check Fuel System Pressure

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "ON" position without starting the engine and check the pressure reading.
  3. Compare the reading to the manufacturer's specifications (typically around 50-60 psi).
  4. If the pressure is low, inspect the fuel pump and fuel filter for issues.
• Tools Required: Fuel pressure gauge.

4. Clean or Replace MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector and remove the sensor.
  3. Clean the MAF sensor with MAF cleaner or replace it if damaged.
  4. Reinstall the sensor and reconnect the electrical connector.
• Tools Required: MAF cleaner, screwdriver.

5. Inspect Fuel Injectors

• Sub-steps:
  1. Remove the fuel rail assembly to access the injectors.
  2. Inspect the injectors for clogs or leaks.
  3. Clean or replace any faulty injectors.
  4. Reassemble the fuel rail and ensure all connections are secure.
• Tools Required: Socket set, injector cleaning kit (if cleaning).

6. Replace Oxygen Sensors (if necessary)

• Sub-steps:
  1. Locate the oxygen sensors in the exhaust system.
  2. Disconnect the electrical connectors and unscrew the sensors using an oxygen sensor socket.
  3. Install new oxygen sensors, ensuring proper torque is applied (typically around 30 lb-ft).
  4. Reconnect the electrical connectors.
• Tools Required: Oxygen sensor socket, torque wrench.