how to clear P0171 and P0174 codes on BMW 5 Series F10/F11 (2010-2017)

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, vacuum gauge, socket set, torque wrench, MAF cleaner.
• Safely park the vehicle on a level surface.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Clean MAF Sensor

1. Locate the MAF sensor in the air intake duct.
2. Disconnect the electrical connector from the MAF sensor.
3. Remove the MAF sensor using the appropriate socket size.
4. Use MAF cleaner to gently clean the sensor elements. Avoid touching them with fingers.
5. Allow the MAF sensor to dry completely before reinstallation.
6. Reinstall the MAF sensor and reconnect the electrical connector.

3. Check for Vacuum Leaks

1. Visually inspect all vacuum hoses and connections for cracks or disconnections.
2. Use a vacuum gauge to test for proper vacuum levels in the intake manifold.
3. If a leak is found, replace the damaged hoses or fittings.
4. If no leaks are identified, proceed to check the intake manifold gaskets.

4. Inspect Fuel Delivery System

1. Connect a fuel pressure gauge to the fuel rail.
2. Turn the ignition on (without starting the engine) to check for the correct fuel pressure as specified by the manufacturer.
3. If fuel pressure is low, inspect the fuel pump, filter, and lines for blockages or failures.
4. Check the operation of the fuel injectors using a multimeter to ensure they are receiving the correct voltage.

5. Clear Trouble Codes

1. Reconnect the negative battery terminal.
2. Use the OBD-II scanner to clear the codes P0171 and P0174 from the engine control module.
3. Start the engine and let it idle for a few minutes, monitoring for any reoccurrence of the codes.