how to fix P0171 code on my BMW 5 Series G30/G31 (2017-2024)

Solution

1. Preparation

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

Tools Required:

• OBD-II scanner
• Screwdriver set
• Torque wrench
• Fuel pressure gauge
• Multimeter
• Cleaning solvent (for MAF sensor)

2. Inspect and Repair Air Intake System

• Step 2.1: Visually inspect all intake hoses and connections from the air filter to the throttle body for any signs of wear, cracks, or loose fittings.
• Step 2.2: If leaks are found, replace the damaged hoses or secure loose connections. Ensure all clamps are tight.

3. Clean or Replace MAF Sensor

• Step 3.1: Locate the MAF sensor in the air intake duct.
• Step 3.2: Disconnect the electrical connector and remove the MAF sensor from the intake duct.
• Step 3.3: Clean the MAF sensor with an appropriate cleaning solvent, allowing it to dry completely before reinstallation. If damaged, replace with a new sensor.

4. Inspect and Test Fuel Delivery

• Step 4.1: Check the fuel pump for proper operation by listening for the pump's sound when the ignition is turned on.
• Step 4.2: Use a fuel pressure gauge to measure fuel pressure at the fuel rail; ensure it meets manufacturer specifications (typically around 50-60 psi for BMW).
• Step 4.3: If pressure is low, check the fuel filter and replace it if clogged. If the filter is clear, consider replacing the fuel pump.

5. Inspect Vacuum Lines

• Step 5.1: Visually inspect all vacuum lines connected to the intake manifold for cracks or disconnections.
• Step 5.2: Replace any damaged vacuum lines to restore proper pressure and eliminate leaks.