Service Engine Light, No Luck

My friend has a 2003 Pontiac Aztec and the service engine light is on. Everywhere he has gone they tell him the computer cannot read the codes. Has anyone else had this problem? Thanks for any help you can give.

I see it's been almost 5 months, but the OBD2 port usually gets its power through the cigarette lighter fuse. If the fuse is good then it could be a broken wire or corroded connection. Hope this helps, Dustin