Audi a6 allroad

When the car is running i can here a buzzing noise coming from underneath the car under the drivers side front door area, it is not the air suspension pump, but it is some type of pump and it runs while car is running and stops when the car is switched off, anyone know what this is please

From when it runs, it sounds most likely to be a fuel pump. I would look at mine to see but I don't know if we have the same engine which could affect it. Mine's a 2.5 TDI (AKE) - what's yours?