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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect for Vacuum Leaks

• Tools Required: Vacuum gauge, smoke machine (optional).
• Sub-steps:
  1. Visually inspect all vacuum hoses for cracks or disconnections.
  2. Use a vacuum gauge to test the intake manifold for leaks; a reading below normal indicates a leak.
  3. If available, use a smoke machine to pressurize the intake system and identify leaks.

3. Clean the MAF Sensor

• Tools Required: MAF sensor cleaner.
• Sub-steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector and remove the sensor.
  3. Spray MAF sensor cleaner on the sensing element and let it dry completely before reinstalling.

4. Test Fuel Pressure

• Tools Required: Fuel pressure gauge.
• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition to the "ON" position (do not start) and check the pressure reading.
  3. Compare the reading to the manufacturer’s specifications; replace the fuel pump or filter if pressure is low.

5. Inspect Oxygen Sensors

• Tools Required: Multimeter (if applicable).
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Check for any visible damage or contamination on the sensor tips.
  3. If necessary, use a multimeter to test the sensor's voltage output; replace if readings are outside specifications.

6. Reassemble and Test

• Reconnect any components removed or disconnected during the repair process.
• Reconnect the negative battery terminal.
• Clear the P0171 code using the OBD-II scanner and take the vehicle for a test drive.