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

Solution

1. Preparation

• Tools Required: OBD-II scanner, fuel pressure gauge, multimeter, socket set, screwdriver set, MAF cleaner.
• Ensure the vehicle is parked on a flat surface, and the engine is cool. Disconnect the negative battery terminal to prevent electrical shock.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses for cracks or disconnections.
  2. Use a smoke machine or carburetor cleaner to identify leaks by applying it around the intake manifold and hoses while the engine is running.
  3. Replace any damaged hoses and reassemble.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector and unscrew the sensor from the duct.
  3. Clean the sensor using a dedicated MAF cleaner. Allow it to dry completely.
  4. Reinstall the sensor and reconnect the electrical connector.

4. Check Fuel System

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail.
  2. Turn the ignition on (do not start the engine) to check the fuel pressure. It should be within the manufacturer specifications (typically around 40-50 psi).
  3. If the pressure is low, inspect the fuel pump, fuel filter, and fuel injectors for issues.

5. Inspect and Test Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Disconnect the electrical connectors.
  3. Use a multimeter to check the voltage output while the engine is running (should fluctuate between 0.1 to 0.9 volts).
  4. Replace any faulty sensors.

6. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0174 code.
  3. Perform a test drive to observe if the check engine light returns and monitor performance.