how to fix P0171 code in BMW 5 Series F10/F11 (2010-2017)

Solution

1. Preparation

• Tools Required: OBD-II scanner, vacuum gauge, multimeter, fuel pressure gauge, basic hand tools (sockets, wrenches), torque wrench.
• Ensure the vehicle is parked on a flat surface, and the engine is cool.
• Disconnect the battery to prevent electrical shorts during repairs.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses connected to the intake manifold, throttle body, and any other associated components for cracks or disconnections.
  2. Use a vacuum gauge to check for proper vacuum levels; any significant deviation indicates a leak.
  3. Replace any damaged hoses or reattach any loose connections.
  4. Recheck for leaks using a smoke machine if available.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor in the intake system, typically between the air filter and throttle body.
  2. Disconnect the MAF sensor electrical connector and remove the sensor from its housing.
  3. Clean the MAF sensor with MAF cleaner spray; do not touch the sensing element.
  4. If the sensor is damaged or faulty, replace it with a new unit.
  5. Reinstall the MAF sensor and reconnect the electrical connector.

4. Test and Replace Fuel System Components

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition to the "ON" position (without starting) to check fuel pressure; it should be within the manufacturer's specified range.
  3. If pressure is low, check the fuel pump, fuel filter, and fuel injectors for proper operation.
  4. Replace any faulty components (fuel pump, filter, or injectors) as necessary.

5. Check Oxygen Sensors

• Sub-steps:
  1. Locate the upstream oxygen sensor(s) in the exhaust system.
  2. Use a multimeter to test the sensor's voltage output; it should fluctuate between 0.1 to 0.9 volts.
  3. If the sensor is not functioning correctly, replace it with a new one.
  4. Reconnect the sensor and check for any exhaust leaks around the installation point.