The 722.6 in the E Class have been replaced for ~$3500 using local or big box rebuilders.

I'd personally get a second opinion for something that expensive or at least post the codes/adapation values here first.

__________________
Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)