Hello , thanks for your question in the autoaid Community.
Your described fault Code means: Rail pressure sensor
This faultcodes Comes if there is a leaky Injector.
By These codes you should check the Injector return quantity to the tank. At your Mercedes Dealers Workshop there have a leak test System. By These System, the mechanic could see which injector is faulty.
I think there is one Injector problemful and These part have to replaced.