X8 Dead in the water. No CEL even in KOEO?

So my X8 has been running great for months with only a CEL for EGR, so i didnt rush to fix it. Was driving today and started dying then firing back up, when it would die the CEL would go off then back on when it would fire again. it died once with a battery light on, then fired back up with the cel on again. Second time it died, it just turns over now, and the CEL isnt on even in KOEO.

Installed diagnostic jumper, No codes or CEL at all.
No Blown Fuses anywhere.
Repaced battery, as it was ancient anyway.

What would cause no CEL in diagnostic mode? Bad alternator? Fried ECU? Help!

Ian