how to fix P0174 code in BMW 5 Series F10/F11 (2010-2017)?

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to ensure safety before starting work.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Vacuum gauge, hose clamps, and a socket set.
• Sub-steps:
  1. Visually inspect all vacuum lines and hoses connected to the intake manifold for signs of wear or cracks.
  2. Use a vacuum gauge to confirm the absence of leaks; a reading outside the normal range indicates a problem.
  3. Replace any damaged hoses or gaskets identified during inspection.

3. Check and Clean the MAF Sensor

• Tools Required: MAF cleaner or electronic cleaner.
• Sub-steps:
  1. Disconnect the electrical connector from the MAF sensor and remove it from the intake.
  2. Spray the MAF sensor with a dedicated cleaner and allow it to dry completely before reinstallation.
  3. Reinstall the MAF sensor and reconnect the electrical connector.

4. Fuel Pressure Test and Repair

• Tools Required: Fuel pressure gauge.
• Sub-steps:
  1. Locate the fuel pressure test port on the fuel rail and connect the gauge.
  2. Turn the ignition to the "ON" position without starting the engine to check the pressure.
  3. Compare the reading with the specifications (usually around 50-60 psi for most BMW engines); replace the fuel pump if low.

5. Inspect and Clean Fuel Injectors

• Tools Required: Injector cleaning kit or replacement injectors.
• Sub-steps:
  1. Remove the fuel rail and carefully pull out the injectors.
  2. Clean the injectors using a cleaning kit or replace them if they are clogged or damaged.
  3. Reinstall the injectors and fuel rail, ensuring all seals are intact.

6. Check Oxygen Sensors

• Tools Required: Multimeter or scan tool.
• Sub-steps:
  1. Disconnect the upstream oxygen sensor on bank 2.
  2. Use a multimeter to test the sensor’s voltage output; it should oscillate between 0.1V and 0.9V when the engine is running.
  3. Replace the oxygen sensor if it is not functioning within this range.