SLS Service Engine Soon Light
 

I own a 2000 SLS with 100,000 miles, and yesterday I was sitting at a drive through window and the car stalled. I restarted it, and the "Service Engine Soon" light came on and stayed on during my 20 mile drive home, but the car drove normally. When I got home I read up on how to enter diagnostic mode, and the displayscrolled quicklythrough every code option, some saying no codes, and a few saying code #### (didn't write them down) history. The display then went to "Clear all codes?", at which point I switched the ignition off, figuring that the code histories would be saved. I took it into a service shop this morning for an engine diagnostic, and I noticed the "Service Engine Soon" light was no longer illuminated. The service shop just called me to tell me that they couldn't find any codes. I havetwo questions:
1. Could I have cleared the code histories and "Service Engine Soon" lightby turning the ignition off in diagnostic mode?
2. Will the codes come back if it is a reoccurring problem?

At this point I'm just having the shop perform the recommended 100,000 mile maintenance, but I'm worried that something is wrong. Any help is greatly appreciated!

RE: SLS Service Engine Soon Light
 

If failure is still present, codes will reset