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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical issues.
• Ensure the engine is cool before starting work.

2. Inspect and Repair Air Intake System

• Sub-steps:
  1. Visually inspect the air intake hoses for cracks or disconnections.
  2. Tighten or replace any loose or damaged hoses.
  3. Check the intake manifold gasket for leaks and replace if necessary.

3. Replace Engine Air Filter

• Sub-steps:
  1. Locate the air filter housing.
  2. Unclip or unscrew the housing cover.
  3. Remove the old air filter and install a new one ensuring proper fit.
  4. Reassemble the housing cover.

4. Test and Repair Fuel System

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail.
  2. Turn the ignition key to the ON position (do not start) and record the fuel pressure reading.
  3. If fuel pressure is low, check the fuel pump and replace if necessary.
  4. Inspect fuel injectors for clogs using a fuel injector cleaning kit.
  5. Replace any faulty injectors.

5. Clean or Replace MAF Sensor

• Sub-steps:
  1. Disconnect the MAF sensor connector.
  2. Remove the MAF sensor from the air intake duct.
  3. Clean the MAF sensor with MAF cleaner spray or replace if cleaning does not resolve the issue.
  4. Reinstall the MAF sensor and reconnect the connector.