Fuel System: How to Bleed Properly

Hello,

I have a Passat 1.6 TDI (engine CAYC) from the year 2010, and I have a question:

'High-pressure pumps should not run dry, otherwise shavings can be generated. How do you properly bleed the system when there is air in the high-pressure system (e.g., due to a high-pressure pump replacement or work on the fuel lines)? Is it sufficient to simply activate the fuel pump for pre-charging in the tank using VCDS? Does the fuel then flow through the entire system, including the high-pressure system? Finally, there is already a return hose from the fuel filter to the tank. After the high-pressure pump, there are also 2 valves (1 valve directly on the fuel rail, 1 pressure regulating valve for the fuel rail, and 1 pressure relief valve on the return line). The pressure must first be overcome before anything can reach the return line from the high-pressure system?'

Sure, here's the translation:

'Thank you in advance!'

Using VCDS to activate the fuel pre-pump will fill the new, empty diesel filter. This process does not flush the high-pressure system, and it doesn't need to.

Best regards, Rainer.