my BMW 3 Series F30/F31 (2012-2019) has a check engine light and P0171 code what's next

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative terminal of the battery for safety.
• Ensure the engine is cool before proceeding.

2. Inspect and Replace MAF Sensor (if necessary)

• Remove the air intake duct that connects to the MAF sensor.
• Disconnect the electrical connector from the MAF sensor.
• Remove the MAF sensor using a Torx screwdriver.
• Clean the MAF sensor with MAF sensor cleaner if it appears dirty; if damaged, replace it with a new sensor.
• Reinstall the MAF sensor and reconnect the electrical connector.

3. Inspect and Repair Vacuum Leaks

• Check all vacuum hoses for cracks or wear and replace any damaged hoses.
• Inspect the intake manifold gasket for signs of wear or leaks and replace if necessary.
• Perform a smoke test to confirm the absence of vacuum leaks.

4. Fuel System Inspection

• Connect a fuel pressure gauge to the fuel rail's service port.
• Turn the ignition to the "ON" position without starting the engine to check the pressure reading.
• Compare the reading with manufacturer specifications (typically around 50-60 psi for most BMWs).
• If the pressure is low, inspect the fuel pump and filter for issues; replace if necessary.

5. Testing Fuel Injectors

• Remove the fuel injector connectors and inspect for damage.
• Use a multimeter to check the resistance of each injector (typically 12-16 ohms).
• If any injectors are out of specification, replace them.