Mercedes Repair Questions? Ask a Mechanic for Answers ASAP
The fault codes you have could relate to a number of items on the injection system.
The faults could lie with any of the following:
I would suggest you carry out a Fuel Pressure Test and see what they shows and go from there.
So you are saying there is no fuel pressure to the fuel rail? If there is fuel to the High Pressure Pump but none out of it then this is likely to be the pump itself or if it has a separate metering valve in the pump it could be that unit that has failed.
Ok so the pump is obviously delivering something to the rail but it is not the required pressure at present. This could be one of two things. Either the pump itself is faulty or one or more injectors are leaking past and not holding pressure.
I would carry out an Injector Leak Test using https://www.ebay.co.uk/itm/6-Cylinder-Diesel-Injector-Flow-Meter-Adaptor-Set-Common-Rail-Leak-Off-Tester/391780064010?epid=7011024174&hash=item5b37e95b0a:g:UF4AAOSwa39Uy6AE
See what results you get from that. You may find one is leaking excessively more than the others in which case it will require injectors. If they all test ok then it will probably require a pump.
What colour is the smoke emitted from the vehicle. If it is Black Smoke this would suggest injector issues with excessive fueling and maybe all of the fuel is not being burnt.