I. Background Info 

https://en.wikipedia.org/wiki/On-board_diagnostics

https://en.wikipedia.org/wiki/OBD-II_PIDs

II. OBD-II Services or Modes

III. SAE J1962  H/W 

IV.OBD-II Protocols 

http://www.obdtester.com/obd2_protocols

https://www.outilsobdfacile.com/communication-norm-obd.php

-The End-