ECU light on all the time

[Sneddo]

I have narrowed it down to pin 22 going into the ECU (the cylinder coil). But I have swapped the coils and it doesn't move and the bike runs perfectly. Does anyone know if positive or ground is the active state (I assume positive). Has anyone had a similar issue?
I suspect the loom or the ECU.

 

[atomsplitter]

Haven't seen it on my T-Bird, so can't really help you. Makes me wonder if the OBD plug has an issue.