Most of the "super abilities" provided by high-end scan tool / ECU flash packages work by using manufacturer-specific data sent over the CAN bus, not OBD-II itself.

Some newer and higher-end cars even use proprietary crypto keyed off of the VIN number and a shared secret to protect from access by third-party tools. There's a good-sized cottage industry in breaking proprietary ECU protocols and crypto, because there's a solid niche market in selling mechanics one $20,000 "multiflash" tool to replace their ten $10000 manufacturer-provided "diagnostic systems," especially in the high-end exotic market.

I was able to find enough resource online to build an ISO OBD-II scanner as my seventh-grade final project, without needing to resort to hunting down the standard. Today there are even open-source projects like http://en.wikipedia.org/wiki/OBDuino which can provide a solid code-based understanding of the three old OBD signaling types (PWM, VPW, ISO), as well as the basic protocol.

I'll let you all get back to topic at hand. I have to say thanks though. I never imagined getting so much helpful info. The super ability I seek seems like it would be in a less secure area because even cheap hardware store tools can do it. I am trying to remove, relocate, or hide fault codes without resetting the emissions monitors. That way as a hush hush marketing ploy of my business I can truly "guarantee to pass" and depending on the solution possibly guarantee to never fail again.

I hit an idea slump in my normal utility making and decided to put my otherwise wasted time to use.

Thanks Again ~

Of all the car I worked on (mostly Mitsubishi and Ssangyong) very few of them had non-standard procedures for erasing DTCs.

I don't know what you mean by 'erasing the emission monitor', unless you mean the freeze frame, which usually gets erased when you erase DTCs with the standard 0x14 request.

Anyway I work exactly as you do, by reverse-engineering official tools.

And I'm not very knowledgeable about cars anyway :)