how to fix P0174 code in my Toyota RAV4 XA50 (2019-2024)

Solution

1. Preparation

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

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
  2. Use a smoke machine or carburetor cleaner to check for leaks around gaskets and hose connections.
  3. Replace any damaged hoses or gaskets as necessary.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Disconnect the MAF sensor harness.
  2. Remove the MAF sensor from its housing using the appropriate screwdriver.
  3. Clean the sensor with MAF cleaner spray. Avoid using any other cleaners.
  4. If the sensor is damaged or cleaning does not resolve the issue, replace it with a new one.
  5. Reinstall the MAF sensor and reconnect the harness.

4. Check and Adjust Fuel Pressure

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition to the "ON" position without starting the engine to check the fuel pressure.
  3. Compare the reading to the manufacturer’s specifications (usually around 30-40 psi for most vehicles).
  4. If pressure is low, inspect the fuel pump, fuel filter, and fuel lines for issues and replace as necessary.

5. Replace Engine Coolant Temperature Sensor (if faulty)

• Sub-steps:
  1. Locate the engine coolant temperature sensor in the engine bay.
  2. Disconnect the wiring harness from the sensor.
  3. Remove the sensor using the appropriate socket or wrench.
  4. Install the new sensor and reconnect the wiring harness.