08 Aveo Hatchback with no Check Engine Light

My daughter took her Aveo to get smogged and they wouldn't even check it because the CEL wouldn't turn on when you turned the key to the on position. This model has the CEL in the clock assembly. The car idles a bit rough but otherwise starts fine and runs fine. I guess I have a few questions.
1) Could it be a bulb or does this model have LED's soldered to the board in the clock?
2) Could it be the ECM? Is there a way to verify that is the issue?
3) Without disassembling the dash is there a way to test the bulb by jumping power to a specific ECM pin location?
4) Does the fact the car idles a bit rough point more toward the ECM being the issue?

It's a 12 year old car so I'm really trying to stay away from the dealer if possible. so any help would be appreciated.