my BMW X5 F15 (2014-2019) has a check engine light and a P0171 code, how to fix it?

Solution

1. Preparation

• Gather tools and parts required.
• Disconnect the battery to ensure safety while working on the vehicle.

2. Inspect Air Intake System

• Tools Required: Screwdrivers, pliers
• Sub-steps:
  1. Visually inspect all hoses and connections from the air filter to the intake manifold for cracks or disconnections.
  2. Use a smoke machine or spray soapy water to check for vacuum leaks.
  3. Replace any damaged hoses found during inspection.

3. Clean the MAF Sensor

• Tools Required: MAF sensor cleaner
• Sub-steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector and remove the sensor.
  3. Spray the MAF sensor with the cleaner and allow it to dry completely before reinstalling.

4. Check Fuel System

• Tools Required: Fuel pressure gauge, socket 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 to check fuel pressure.
  3. Ensure pressure meets specifications; if not, check the fuel pump and filter.
  4. If the fuel filter is clogged, replace it.

5. Inspect and Test Fuel Injectors

• Tools Required: Multimeter, injector cleaning kit
• Sub-steps:
  1. Disconnect the fuel injector electrical connectors.
  2. Use a multimeter to check for proper voltage and resistance.
  3. If an injector is faulty, replace it.
  4. Use an injector cleaning kit to clean the injectors if they are functioning but dirty.

6. Reassemble and Clear Codes

• Tools Required: OBD-II scanner
• Sub-steps:
  1. Reconnect all components and hoses removed during the inspection and repair process.
  2. Reconnect the battery.
  3. Use the OBD-II scanner to clear the P0171 code and check for any new codes.