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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, fuel pressure gauge, multimeter, carburetor cleaner, vacuum gauge.
• Ensure the engine is cool and the vehicle is in a safe, well-ventilated area.
• Disconnect the battery to prevent any electrical issues.

2. Inspect and Repair Air Intake System

1. Remove the engine cover if necessary to access the intake system.
2. Visually inspect all intake hoses for cracks or loose connections.
3. If any damage is found, replace the affected hoses.
4. Reconnect all hoses securely and replace the engine cover.

3. Clean or Replace MAF Sensor

1. Disconnect the electrical connector from the MAF sensor.
2. Remove the MAF sensor from the air intake duct using the appropriate socket.
3. Clean the MAF sensor with MAF cleaner spray, avoiding contact with the sensor element.
4. Allow it to dry completely before reinstalling.
5. Reinstall the MAF sensor and reconnect the electrical connector.

4. Check and Adjust Fuel Delivery

1. Connect a fuel pressure gauge to the fuel rail.
2. Start the engine and check the fuel pressure reading against the specifications (typically around 50-60 psi for BMW).
3. If the fuel pressure is low, check the fuel pump and fuel filter for clogs or failures, replacing them as necessary.
4. If the pressure is normal, proceed to inspect the injectors.

5. Repair Vacuum Leaks

1. With the engine running, carefully spray carburetor cleaner around the intake manifold and hoses.
2. Listen for changes in engine RPM, indicating a vacuum leak.
3. If a leak is detected, replace the faulty gasket or hose.
4. Recheck all connections to ensure they are tight.