I've got a 2002 stilo.
The battery went flat,so I trickle charged it over night.
The next day,it wouldn't start.
I'm a mechanic and I've got the diagnostic gear to sort it out,but,and it's a big but.
I can't get it to communicate with the car anymore.
No engine management light on the dash.
I've checked all the connectors,and the battery is holding 12.8 v.

hows your fuses looking?
have you tried disconnecting the battery for half an hour or so then reconnecting it?

im sure someone had this recently but i cant remember the outcome. it seems to be more and more time between when i can get on here nowadays thanks to a new job.