how to diagnose P0171 and P0174 codes on my BMW 5 Series F10/F11 (2010-2017)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative terminal of the battery to ensure safety.
• Allow the engine to cool before starting work.

2. Inspect and Repair Air Intake System

• Tools Required: Socket set, screwdrivers, flashlight
  • 1. Visually inspect all air intake hoses and connections for cracks or disconnections.
  • 1. Tighten any loose clamps or replace damaged hoses.
  • 1. If leaks are found, replace the affected components.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, torx screwdriver
  • 1. Remove the MAF sensor from the air intake system using a torx screwdriver.
  • 1. Spray the MAF sensor with MAF sensor cleaner and allow it to dry completely.
  • 1. Reinstall the MAF sensor securely, ensuring that all connectors are tight.

4. Check and Repair Fuel System

• Tools Required: Fuel pressure gauge, socket set
  • 1. Connect a fuel pressure gauge to the fuel rail Schrader valve.
  • 1. Turn the ignition to the "ON" position (do not start the engine) and check the fuel pressure reading.
  • 1. If the pressure is below specifications, inspect the fuel pump and filter for issues.
  • 1. Replace the fuel filter if it appears clogged, and if necessary, replace the fuel pump.

5. Inspect Vacuum Lines

• Tools Required: Visual inspection tools, vacuum gauge (optional)
  • 1. Visually inspect all vacuum lines for cracks or wear.
  • 1. Replace any damaged lines to ensure proper vacuum levels.
  • 1. If available, use a vacuum gauge to check for proper readings.