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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the vehicle battery to ensure safety.

Tools Required:

• OBD-II scanner
• Multimeter
• Socket set
• Torque wrench
• Vacuum gauge
• Fuel pressure gauge

2. Inspect and Repair Vacuum Leaks

1. Visually inspect all vacuum hoses connected to the intake manifold and the throttle body.
2. Replace any damaged or cracked hoses.
3. Use a smoke machine or vacuum gauge to test for leaks in the intake manifold and associated gaskets.

3. Clean or Replace MAF Sensor

1. Remove the MAF sensor from the intake duct.
2. Clean the MAF sensor with MAF sensor cleaner, ensuring not to touch the sensing element.
3. If cleaning does not resolve the issue, replace the MAF sensor with a new one.

4. Check Fuel System

1. Connect a fuel pressure gauge to the fuel rail.
2. Turn the ignition to the "ON" position (without starting the engine) and check the fuel pressure; it should meet manufacturer specifications.
3. If pressure is low, inspect and replace the fuel filter and check the fuel pump operation.
4. If necessary, replace the fuel pump.

5. Inspect Oxygen Sensors

1. Use a multimeter to check the voltage output of the upstream oxygen sensor.
2. If the sensor readings are outside of manufacturer specifications, replace the oxygen sensor.

6. Reassemble and Reconnect

1. Reassemble all components and hoses removed during the inspection and repair.
2. Reconnect the battery.