I have been working on this issue for months now and not much closer to solving the problem. It goes into no turbo boost within 2 minutes of start up. CODES P0400(P1403) and P0243
I have read the previous post by Turbodiesel (mercedesshop.com/shopforum/showthread.php?t=118125) that was started years ago and solved by some very good help from all and with a detailed post from Dr.Diesel
I have replaced parts, because of finding bad components. MAF, EGR valve assembly, all plastic fuel lines, intake manifold removed and replaced and cleaned, replaced all vacuum hoses, installed a boost and vacuum gauge, checked the pressure supply, wiring. I replaced the vent filters.
The EGR and Turbo pressure transducer are only showing 0.018 DC amps which is low according to Dr. Diesel.

??What causes this low current draw??
??What fuses protect these circuits so that I can check for fuse corrosion at the bayonet connectors??

During the first 2 minutes of operation I get 20 pounds of boost and the car is fast and after that time the boost is 0-3 psi and it is a dog!
The EGR valve had been opened up and the innards had been removed by a previous owner, but the turbo worked fine until I overheated it and it went into full limp home mode and I was put on the piggy back wrecker and brought home.
Wife drives it every day but I have the need for more power. I am about ready to send it to the dealership for a fix.
Am driving to Blythe this w/e so pass with care when you go past the non turbo E300.

Thanks in advance!
Larry12
1998 E300-606.962
1987 300-603.960
1993 8.3 TD Cummings