how to fix P0174 code on BMW 5 Series G30/G31 (2017-2024)

Solution

1. Preparation

• Tools Required: OBD-II scanner, vacuum gauge, fuel pressure gauge, torque wrench, socket set, MAF cleaner, basic hand tools.
• Safety Warnings: Disconnect the battery before starting work on electrical systems; allow the engine to cool before working on intake components.

2. Inspect and Repair Vacuum Leaks

1. Use a vacuum gauge to check the intake system for leaks.
2. If leaks are found, replace damaged vacuum hoses or intake manifold gaskets as necessary.
3. Reconnect any disconnected hoses securely.

3. Clean the Mass Airflow Sensor

1. Remove the MAF sensor from the intake ducting.
2. Spray MAF cleaner onto the sensor elements to remove dirt and contaminants.
3. Allow the sensor to dry completely before reinstalling.

4. Check and Adjust Fuel Pressure

1. Connect the fuel pressure gauge to the fuel rail test port.
2. Turn the ignition on (do not start the engine) and observe the fuel pressure reading.
3. If the pressure is below the specification, check the fuel pump and fuel filter. Replace if necessary.

5. Inspect and Replace Fuel Injectors (if needed)

1. Remove the fuel rail by unbolting it from the intake manifold.
2. Disconnect the electrical connectors from the fuel injectors.
3. Remove the injectors and inspect them for clogs or wear; clean or replace as necessary.
4. Reinstall the fuel rail and connect the injectors securely.

6. Reassemble and Test

1. Reconnect all components removed during the repair process.
2. Reconnect the battery.
3. Clear the P0174 code using the OBD-II scanner.