BAS/ESP lights in most cases the result of a bad sensor somewhere. Sensors are located at all 4 wheels, inside the center console (yaw rate), steering angle, and I may be wrong about this part but there might be sensors in the differential and transmission as well.

You're correct about an ordinary OBDII reader being unable to read those codes. You'd need a reader with ESP libraries for MB models of that time. I've seen people read those codes by setting the reader to SLK320 (obviously) and even C32. That will at least tell which sensor is at fault.

Doing a search here or even in the owners manual you'll find info on how to reset the steering sensor. I guess that works for some but I've never seen that work personally.