how to fix P0174 code on my Toyota RAV4 XA40 (2013-2018)

Solution

1. Preparation

• Gather tools and parts needed.
• Disconnect the battery by removing the negative terminal.
• Allow the engine to cool completely 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 identify vacuum leaks by spraying around suspected areas and observing for RPM changes.
  3. Replace any damaged hoses or gaskets.

3. Check and Clean the MAF Sensor

• Sub-steps:
  1. Locate the mass airflow sensor in the intake duct.
  2. Disconnect the electrical connector and carefully remove the MAF sensor.
  3. Clean the MAF sensor using MAF sensor cleaner; avoid touching the sensor element.
  4. Reinstall the MAF sensor and reconnect the electrical connector.

4. Test Fuel Pressure

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail Schrader valve.
  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; if low, check the fuel pump and filter.
  4. If necessary, replace the fuel filter or fuel pump.

5. Inspect Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on bank 2.
  2. Disconnect the electrical connectors and remove the sensors using an oxygen sensor socket.
  3. Inspect the sensors for contamination; replace if they are damaged or excessively fouled.
  4. Reinstall the new or cleaned sensors and reconnect the electrical connectors.