My CEL popped on at 800km, stayed on for about 24 hours, then went out and I didn't see it again for about a week. My suspicion is that the gas cap wasn't on tight enough, but not positive that was it.
CEL came on again just shortly after fillling tank a couple days ago, so maybe its as another poster said, its from overfilling tank. This time it hasn't gone away yet (about 100km driven so far, lots of stops and starts).
Solid CELs (emissions based CELs) that are intermittent need a certain number of engine starts and stops without the original problem before the CEL goes out again, so if the overfilled tank was the issue, the CEL should clear shortly.
I have AutoTap OBD2 kit from a couple years ago (used it on my '99 Miata), but not sure if I bought the CAN upgrade. Does the MSM6 use the OBD2 or CAN protocol through its diagnostic port?
For that matter, where the heck IS the diagnostic port in the MSM6 cabin? I haven't crawled right under the dash yet, but its not where it was in the Miata (nice and handy just under the dash by the driver side fuse panel).