how to fix P0174 code in my BMW X5 F15 (2014-2019)?

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to prevent electrical shorts during the repair process.
• Allow the engine to cool before starting work.

2. Inspect Vacuum Hoses and Gaskets

• 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 detect leaks around the intake manifold gaskets.
  3. Replace any damaged hoses or gaskets.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Disconnect the electrical connector from the MAF sensor.
  2. Remove the MAF sensor from the intake duct.
  3. Clean the sensor element with MAF cleaner (do not use other solvents).
  4. Reinstall the MAF sensor and reconnect the electrical connector.

4. Check and Adjust Fuel Pressure

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail.
  2. Turn the ignition on (without starting the engine) and check the fuel pressure; it should meet manufacturer specifications (typically around 50-60 psi for BMW).
  3. If pressure is low, check the fuel pump and filter for clogs or failures, replacing as necessary.

5. Inspect Fuel Injectors

• Sub-steps:
  1. Remove the fuel rail to access the fuel injectors.
  2. Inspect the injectors for clogs or leaks.
  3. Clean the injectors using a cleaning kit or replace them if they are faulty.
  4. Reinstall the fuel rail and ensure proper sealing.

6. Verify Oxygen Sensor Functionality

• Sub-steps:
  1. Use a multimeter to check the voltage and response of the upstream oxygen sensor on bank 2.
  2. Replace the oxygen sensor if it shows signs of malfunction (staying high or low without fluctuating).