You might see if the info is in the manual. See if one of these sites work.
W126 FSM:
http://www.startekinfo.com/StarTek/outside/12253/?requestedDocId=12253

W126
Untitled Document

http://www.w124performance.com/service/W126/Main.html

126 CD 1
http://www.w124performance.com/service/W126/w126CD1/program/matrix.htm
126 CD 2
http://www.w124performance.com/service/W126/w126CD2/program/matrix.htm

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84 300D, 82 Volvo 244Gl Diesel