What we are looking for is that the engine computer is waking up. ( look at sensor data and see if it is believable. ) A generic OBD2 scanner will tell you that.

On my 97 C280 / E320 / SL320 a Snap on "red brick" scanner with Mercedes SW will tell me if the DAS chip in a key module is locked to the engine computer. However this is a generation prior to your car.