I know exactly what you are talking about 97 SL320. I had the same problem on my 98 E320's trans controller. Taking this into account one of the first things I checked was the inside of the ABC module and it was perfectly clean. This doesn't mean that the module is not at fault, Im actually thinking it is, but it has no oil inside and looks brand new.

Is there some way to test these modules without just throwing down $1400 and hoping it works?