how to fix P0171 code in BMW 3 Series G20/G21 (2019-2024)?

Solution

1. Preparation

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

2. Inspect and Repair Air Intake System

• Sub-steps:
  • Visually inspect all air intake hoses and the intake manifold for cracks or disconnections.
  • Tighten or replace any loose or damaged hoses.
  • Clean the MAF sensor with MAF cleaner to remove any debris.

Tools Required:

• Screwdriver set
• Pliers
• MAF sensor cleaner

3. Check and Adjust Fuel System

• Sub-steps:
  • Connect a fuel pressure gauge to the fuel rail and check the pressure against manufacturer specifications (typically around 50-60 psi).
  • If pressure is low, inspect the fuel pump, fuel filter, and fuel lines for blockages or damage.
  • If necessary, replace the fuel filter and consider replacing the fuel pump if it is not functioning correctly.

Tools Required:

• Fuel pressure gauge
• Socket set

4. Inspect and Replace Engine Sensors

• Sub-steps:
  • If the coolant temperature sensor is faulty, replace it with a new one.
  • For a faulty MAF sensor, replace it with an OEM part.

Tools Required:

• Socket set
• Torque wrench for reinstallation of sensors

5. Reassemble and Test

• Sub-steps:
  • Reconnect all hoses, wiring, and battery terminals.
  • Clear the error codes from the OBD-II system.
  • Start the engine and let it idle to check for any new codes and ensure smooth operation.