Std 14230

=ISO-14230= Also known as "KWP 2000". At a lower level, almost identical to the older ISO-9141 protocol. The standard is in multiple parts : The most relevant for our needs are parts 2 and 3.
 * 1) ISO14230-1 basics, electrical + phys
 * 2) ISO14230-2 Message formatting, bus initialization
 * 3) ISO14230-3 Definition of standard Service ID (SID)s.
 * 4) ISO14230-4 Application to emissions stuff

Links
Of course google will help.
 * https://en.wikipedia.org/wiki/Keyword_Protocol_2000
 * http://www.iso.org/iso/catalogue_detail.htm?csnumber=55592 : official ISO14230-2, $$$
 * http://www.iso.org/iso/catalogue_detail.htm?csnumber=23921 : official ISO14230-3, $$$
 * https://law.resource.org/pub/us/cfr/ibr/004/iso.14230-4.2000.pdf US adoption of one (less interesting part of the standard
 * http://www.alfa145.co.uk/obd/14230-3s.pdf Swedish implementation (SSF-14230), mostly identical.