my BMW 5 Series F10/F11 (2010-2017) has a check engine light and code P0171, what does it mean?

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is turned off.
• Disconnect the negative battery terminal to prevent any electrical shorts.

2. Inspect Air Intake System

• Sub-steps:

  1. Visually inspect the air intake duct and hoses for cracks or disconnections.
  2. Tighten any loose clamps and replace damaged hoses.
  3. Check the air filter for cleanliness; replace if necessary.

• Tools Required:

  • Screwdriver set
  • Pliers

3. Clean MAF Sensor

• Sub-steps:

  1. Locate the MAF sensor on the air intake duct.
  2. Disconnect the electrical connector and remove the sensor.
  3. Clean the MAF sensor with MAF sensor cleaner spray.
  4. Allow the sensor to dry completely before reinstalling.

• Tools Required:

  • Torx screwdriver
  • MAF cleaner spray

4. Test Fuel Pressure

• Sub-steps:

  1. Connect a fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition to the ON position (do not start) to prime the fuel system.
  3. Check the fuel pressure reading against manufacturer specifications.
  4. If the pressure is low, check the fuel pump and filter.

• Tools Required:

  • Fuel pressure gauge

5. Inspect Fuel Injectors

• Sub-steps:

  1. Use a multimeter to check the resistance of each fuel injector.
  2. If an injector is out of specification, replace it.
  3. Ensure the injector connectors are secure and free of corrosion.

• Tools Required:

  • Multimeter