how to resolve the P0171 lean condition code in my BMW 3 Series G20/G21 (2019-2024)?

Solution

1. Preparation

• Ensure the vehicle is parked on a level surface.
• Disconnect the battery to prevent electrical shorts.
• Gather tools and parts needed for the repair.

2. Inspect and Repair Air Intake System

• Tools Needed: Vacuum gauge, hose clamps, screwdriver.
• Sub-steps:
  1. Examine all vacuum hoses connected to the intake manifold. Replace any cracked or damaged hoses.
  2. Inspect the intake manifold gasket for leaks. Replace if necessary.
  3. Use a vacuum gauge to test for leaks—correct any issues found.

3. Clean or Replace MAF Sensor

• Tools Needed: MAF sensor cleaner, torx screwdriver.
• Sub-steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Carefully disconnect the electrical connector.
  3. Remove the MAF sensor from its housing.
  4. Clean the sensor with MAF cleaner and allow it to dry.
  5. Reinstall the MAF sensor and reconnect the electrical connector.

4. Check Fuel Delivery System

• Tools Needed: Fuel pressure gauge, wrench set.
• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "ON" position without starting the engine and check the fuel pressure.
  3. Compare the reading to manufacturer specifications (typically 50-60 psi for BMW).
  4. If pressure is low, inspect the fuel pump and fuel filter for issues and replace as needed.

5. Inspect Fuel Injectors

• Tools Needed: Injector cleaning kit, multimeter.
• Sub-steps:
  1. Use a multimeter to test the resistance of each injector. Replace any that are out of specification.
  2. If injectors are clogged, use an injector cleaning kit to clean them thoroughly.

6. Verify Throttle Body Function

• Tools Needed: Throttle body cleaner, screwdriver.
• Sub-steps:
  1. Remove the throttle body from the intake manifold.
  2. Clean the throttle plate and housing using throttle body cleaner.
  3. Reinstall the throttle body and ensure all connections are secure.