what does it mean if I get a 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 prevent electrical shorts.
• Allow the engine to cool down before starting work.

2. Inspect and Repair Air Intake System

• Sub-step 1: Visually inspect all vacuum hoses and connections for cracks or disconnections. Replace any damaged hoses.
• Sub-step 2: Check the intake manifold gasket for leaks. If found, replace the gasket using a torque wrench to tighten bolts to the manufacturer's specified torque.

3. Clean or Replace MAF Sensor

• Sub-step 1: Locate the MAF sensor in the air intake. Disconnect the electrical connector and carefully remove the sensor from its housing.
• Sub-step 2: Clean the MAF sensor using MAF cleaner spray. Allow it to dry completely before reinstalling.
• Sub-step 3: If the MAF sensor is faulty, replace it with a new unit and reconnect the electrical connector.

4. Check Fuel Pressure

• Sub-step 1: Connect a fuel pressure gauge to the fuel rail. Turn the ignition to the "On" position without starting the engine to check the pressure reading.
• Sub-step 2: Compare the reading to the manufacturer's specifications. If the pressure is low, check the fuel pump and filter for faults.

5. Inspect Fuel Injectors

• Sub-step 1: Remove the fuel injectors from the fuel rail. Inspect for any signs of clogs or leaks.
• Sub-step 2: Clean the fuel injectors using an ultrasonic cleaner or replace them if necessary, ensuring proper sealing during reinstallation.