I know Benz in 1997 just suppot OBD1 38pin connector. But md802 only use obd16.

 The coverage information for R129 Mercedes as of 09/99 on MD802 All Systems version 3.11 is here:

http://104.171.4.62:8800/Download/Veh/ELITE/Enhanced/Benz/en_MaxiDiag_E_Benz%20FUNCLIST.pdf

R129 coverage begins on page 93 of the PDF

It looks like it would read and erase codes for ME1 and ME2 motor electronics and ETC electronic transmission control. Not sure if these are the same systems on a 1997 model, and not sure if read & clear would be sufficient to get it out of limp home. I'd be curious to know if any older versions of the software would reach back to a 1997 - I suspect they drop older models as they go on to newer versions.  I kept intact the original 1.0 card when I got the MD802, and also a 2.0 card when they did the major upgrade to include live data.  Also, you would need a properly wired up 38 pin adapter, which has been elusive for me.