You need to get the proper item name before I can give you any help. There is no such thing as a shifter control module.

There is an Engine Control Module and a Transmission Control Module, both of which are integral parts of the computer systems that run your car. Neither is a DIY repair since they must be programmed to each specific car through the DRB port.

If you're looking to have it done (non-warranty) I would have an independent mercedes mechanic do the repairs. Once you identify which item is faulty (correct part name) post it here, there may be a way to try to re-program the faulty part without having to purchase a new one.