P1470 Fault Boost pressure control

[Larry12]

I paid $200.00 to get a readout on my 1998 e300td(210.025 606.962).
They will fix the problem,they think, for another $800.00. I would just as soon do the work myself. Where do I purchase an intake or boost pressure controller new , used or repair kit? I locked the turbo into full boost mode and it worked great until the fuel supply could not keep up with that much boost.

Thanks in advance.