how to fix P0171 code in BMW 3 Series F30/F31 (2012-2019)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to prevent any electrical issues during repair.
• Tools required: OBD-II scanner, multimeter, fuel pressure gauge, socket set, torque wrench, vacuum gauge, cleaning supplies (MAF cleaner, etc.).

2. Inspect and Repair Air Intake System

• Sub-step 1: Visually inspect all vacuum hoses and connections for cracks or loose fittings.
• Sub-step 2: Replace any damaged hoses or gaskets found during inspection.
• Sub-step 3: Tighten any loose connections securely.

3. Check and Clean MAF Sensor

• Sub-step 1: Locate the MAF sensor in the air intake duct.
• Sub-step 2: Remove the sensor by unscrewing it (if applicable) and disconnecting the electrical connector.
• Sub-step 3: Clean the sensor with MAF sensor cleaner and allow it to dry completely before reinstallation.

4. Test Fuel Pressure

• Sub-step 1: Connect the fuel pressure gauge to the fuel rail.
• Sub-step 2: Turn the ignition on (without starting the engine) and check the readings; they should match the manufacturer's specifications.
• Sub-step 3: If the pressure is low, check the fuel pump and fuel filter for issues and replace them if necessary.

5. Inspect Fuel Injectors

• Sub-step 1: Remove the fuel injector connectors and inspect for any visible damage.
• Sub-step 2: Perform a resistance test on the injectors with a multimeter to ensure they are within specifications.
• Sub-step 3: If any injector is faulty, replace it with a new one.