2004 E320 4-Matic Wagen Tranny issue

[fast_freddy]

Ladies and Gentlemen,

New to this forum but not MB (have had two E320's and an E63 in the past).

My son has a 2004 Mercedes E320 4-Matic wagen (135k miles) that recently has encountered a transmission issue. The car is currently in "limp home mode" where the tranny wont shift from second gear. It's throwing the code P0715 "Input/Turbine Speed Sensor A Circuit". I replaced the connector plug (was leaking) and replaced the conductor plate as well. The code remains (it re-appears after I clear it with my generic OBDII tool) and the tranny wont shift out of second.

Is this something that only a MB dealer can "reset" with the Star tool rather than me just resetting it with my OBDII tool? Or.... is there another issue?

I've perused all the MB forums with no result. Stumped....

Thank you so much for your help.