If you've read my first Mode $06 article (Mode $06--A Tech's Perspective), you already have a good idea of how the ECM monitors and individual tests are run, and you also know that the test results for many of these monitors is available in this mode. At the time, the major drawbacks to using Mode $06 as a diagnostic tool was lack of information. Most tests were listed with hexadecimal test results that meant nothing to us as technicians. Even what the tests were was often hard to find out...all we had was a list of results in what was, for all practical purposes, gibberish, and all we could really tell was that the individual tests had either passed or failed.
CAN made it easier...with these test results listed in actual values and not requiring a correction factor to make the "computer" numbers into something we could work with...but still identifying the tests themselves took access to factory service information, generally for a fee.
Today all that has changed. Both the major service information providers, Alldata and Mitchell On Demand, are including Mode $06 information in their systems. The completeness of the information varies by manufacturer...some is very good, some is OK...but at least it's there. Now you can find out what the failed TID $03--CID $54 actually tested and what monitor it belongs to. If the conversion factor is there, you can easily translate the data if your scan tool doesn't already do this for you.
I noted from the beginning that Mode $06 was good for a few things...gaining diagnositic direction and verifying your repair. As long as you understand how the monitor is run, and how the system is being tested, this ability to get the Mode $06 information you need to identify the test and interpret the data makes Mode $06 that much more useful. I still don't think it is a diagnostic end in and of itself, but it does cut down on my diagnostic strategy in many cases...after all, who's going to test the system more thoroughly...me or that ECM?
(Note: Keep an eye on the "Shop Tales" section for an online exclusive case study of using Mode $06 for diagnosing a P0421 cat efficiency code.)
