my BMW X5 F15 (2014-2019) has a service engine light and poor fuel economy, what to do?

Solution

1. Preparation

• Gather tools: OBD-II scanner, socket set, multimeter, torque wrench, and diagnostic tools for fuel pressure testing.
• Ensure the vehicle is parked on a flat surface and the engine is cool.

2. Address Error Codes

• Use the OBD-II scanner to retrieve and document any trouble codes.
• Clear the error codes and perform a test drive to see if they return, indicating persistent issues.

3. Fuel System Inspection

• Fuel Filter Replacement

  1. Relieve fuel system pressure.
  2. Disconnect the fuel lines from the filter using a line removal tool.
  3. Remove the old filter and install the new one, ensuring proper orientation.
  4. Reconnect the fuel lines and check for leaks.

• Fuel Pump Testing

  1. Use a fuel pressure gauge to check the fuel pump's output pressure against manufacturer specifications.
  2. If out of range, replace the fuel pump.

4. Air Intake Examination

1. Inspect the air filter and replace it if dirty.
2. Check the MAF sensor:
   • Remove the MAF sensor connector and clean the sensor with MAF cleaner.
   • Reconnect and ensure proper operation.

5. Ignition System Service

• Spark Plug Replacement
  1. Remove the ignition coils using a socket.
  2. Remove the old spark plugs using a spark plug socket.
  3. Install new spark plugs, ensuring proper gap and torque specification (typically 20 Nm).
  4. Reinstall ignition coils.

6. Exhaust System Check

1. Inspect the catalytic converter for signs of blockage or damage.
2. If necessary, replace the catalytic converter following manufacturer specifications for installation and torque values.