how to fix P0171 and P0174 codes in BMW X5 F15 (2014-2019)?

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to ensure safety during the repair process.

Tools Required:

• OBD-II scanner
• Socket set
• Torque wrench
• MAF sensor cleaner
• Smoke machine (for smoke test)
• Vacuum gauge

2. Inspect and Repair Air Intake System

• Sub-steps:
  1. Remove the engine cover and air intake duct to access the air intake system.
  2. Visually inspect all intake hoses and connections for cracks or disconnections.
  3. If any damage is found, replace the damaged hoses or clamps.
  4. Reinstall the intake duct and engine cover, tightening all clamps securely.

3. Clean MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor on the air intake system.
  2. Carefully disconnect the electrical connector from the MAF sensor.
  3. Remove the MAF sensor using the appropriate socket.
  4. Spray MAF sensor cleaner onto the sensor wire (do not touch it) and allow it to dry.
  5. Reinstall the MAF sensor and reconnect the electrical connector.

4. Check and Repair Fuel Delivery

• Sub-steps:
  1. Inspect the fuel filter for clogging; replace if necessary.
  2. Test the fuel pump operation by checking fuel pressure at the fuel rail using a fuel pressure gauge.
  3. If pressure is low, replace the fuel pump.

5. Inspect Vacuum Lines

• Sub-steps:
  1. Trace all vacuum lines from the intake manifold to other components.
  2. Replace any cracked or damaged vacuum hoses.
  3. Ensure all connections are tight and secure.

6. Smoke Test for Vacuum Leaks

• Sub-steps:
  1. Connect the smoke machine to the intake system.
  2. Introduce smoke and observe for leaks.
  3. Repair any identified leaks found during the smoke test.