how to fix P0171 code in BMW 5 Series G30/G31 (2017-2024)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the vehicle battery to ensure safety during the repair process.

2. Inspect and Repair Air Intake System

• Tools Required: Socket set, screwdrivers, vacuum gauge
• Sub-steps:
  1. Visually inspect the air intake hoses and connections for cracks or loose fittings.
  2. Tighten any loose clamps or replace damaged hoses.
  3. If a leak is detected, replace the affected air intake components.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, screwdriver, torque wrench
• Sub-steps:
  1. Disconnect the MAF sensor connector.
  2. Remove the MAF sensor from the air intake duct.
  3. Clean the MAF sensor using a dedicated MAF cleaner.
  4. Allow it to dry completely, then reinstall it and reconnect the electrical connector.

4. Inspect Fuel System

• Tools Required: Fuel pressure gauge, socket set
• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail to check for proper fuel pressure.
  2. If the pressure is low, inspect the fuel pump and filter for issues.
  3. Replace the fuel filter if it is clogged.
  4. Test the fuel injectors for proper operation and replace them if necessary.

5. Check for Vacuum Leaks

• Tools Required: Vacuum gauge, smoke machine (optional)
• Sub-steps:
  1. Use a vacuum gauge to test for normal readings.
  2. If readings are low, inspect all vacuum hoses and gaskets for leaks.
  3. Replace any damaged hoses or gaskets found during the inspection.

6. Replace Oxygen Sensors (if necessary)

• Tools Required: O2 sensor socket, torque wrench
• Sub-steps:
  1. Identify the location of the upstream oxygen sensor(s) on Bank 1.
  2. Disconnect the sensor connector.
  3. Use the O2 sensor socket to remove the old sensor.
  4. Install the new sensor and torque it to the manufacturer's specifications.
  5. Reconnect the sensor connector.