how to troubleshoot P0174 code in BMW 5 Series G30/G31 (2017-2024)

Solution

1. Preparation

• Gather the necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal for safety.

2. Inspect and Repair Vacuum Lines

• Sub-steps:
  • Visually inspect all vacuum lines connected to the intake manifold.
  • Replace any damaged or cracked vacuum hoses with OEM-quality parts.
  • Ensure all connections are secure and free from leaks.

3. Clean Mass Airflow Sensor (MAF)

• Tools Required: MAF cleaner spray
• Sub-steps:
  • Disconnect the wiring harness from the MAF sensor.
  • Remove the MAF sensor from the intake duct.
  • Spray MAF cleaner onto the sensor element and allow it to dry completely before reinstalling.
  • Reconnect the MAF sensor and wiring harness.

4. Check Fuel System Pressure

• Tools Required: Fuel pressure gauge
• Sub-steps:
  • Locate the fuel pressure test port on the fuel rail.
  • Connect the fuel pressure gauge to the test port.
  • Turn the ignition to the "ON" position (do not start the engine) and check the pressure reading.
  • If the pressure is below specifications (check the service manual for the specific value), consider replacing the fuel filter or fuel pump.

5. Inspect and Clean Intake Components

• Sub-steps:
  • Remove the throttle body from the intake manifold.
  • Inspect for carbon buildup and use throttle body cleaner to clean the surface.
  • Check the intake manifold for any signs of leaks or damage and replace if necessary.
  • Reinstall the throttle body ensuring all gaskets are intact.