[Gmecm] Clearing fault codes

[Robin Handley]

I've been trying to get rid of some spurious fault codes and I've realised
that I'm not exactly sure how they latch.

If the fault (e.g. 33 - MAP too HIGH) goes away, after it has been present,
should the flag automatically clear? Or is a total ECM reset required? I've
had no luck with using ALDL commands to clear malfs. Is it required to
remove all power from the ECM? If so, for how long?

Robin