After geting my truck smoged today the SES light came on. I watched the guy do it, when he went to shut the truck off ofter the inspection, the light came on just before he turned it off. He looked kinda bewildered, ( No surprise), he checked the codes and then said its alright, it passed. I check the codes, 12 and 42. Do any of you think this guy messed something up? I know he unpluged the wire at the firewall to check the timing, and he double checked it after he noticed the codes? Anyone have any Ideas??