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

Solution

1. Preparation

• Tools Required: OBD-II scanner, vacuum gauge, fuel pressure gauge, multimeter, socket set, cleaning supplies.
• Disconnect the negative terminal of the battery to prevent electrical shorts.
• Allow the engine to cool before proceeding with any work.

2. Inspect for Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum lines for cracks or disconnections.
  2. Use a vacuum gauge to check if the engine is maintaining proper vacuum levels.
  3. If leaks are found, replace damaged hoses or reseal connections.

3. Check Fuel Pressure

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail service port.
  2. Turn the ignition to the "ON" position without starting the engine to prime the fuel system.
  3. Check the gauge reading against manufacturer specifications (typically 50-60 psi for most Toyota models).
  4. If pressure is low, inspect the fuel pump and filter for issues.

4. Inspect 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 spray to remove dirt and debris.
  4. Reinstall the sensor and reconnect the electrical connector.

5. Examine Fuel Injectors

• Sub-steps:
  1. Remove the engine cover to access the fuel injectors.
  2. Inspect the injectors for signs of leakage or clogging.
  3. If clogs are present, use a fuel injector cleaner or replace the injectors as necessary.

6. Reassemble and Test

• Sub-steps:
  1. Reconnect any components removed during the inspection.
  2. Reconnect the negative battery terminal.
  3. Start the engine and allow it to reach operating temperature.