Diagnostic Codes

[mikemartin1939]

This is my first post so I hope someone can answer my question. I have been looking everywhere for the answers but apparently I haven't found the correct place yet.
My 1991 500SL has several Diagnostic ports/connectors where codes or other information can be accessed. These are; X11 a 9 pin, X11/2 (A) and X11/3 (B) both 8 pin and all are located in the EZL/AKR area, X11/4 a 16 pin located in the right side electronics area and X11/22 an OBD port located under the left side of the dashboard. I think that I have the X11/4 and X11/22 code ports covered but I would like to know where to find the information/values associated with the X11, X11/2 and X11/3 ports/connectors. Any help would be greatly appreciated.