Diagnostic codes with paper clip-Cutless Supreme

1991 Oldsmobile Cutless Supreme, 3.1--no spark
When I use the paper clip method to get the codes, (Service Engine Soon)
and connect A to B, I get nothing exept the Service Engine soon light, and the Main cooling fan turns on. What am I doing wrong? Thanks

Idiot at work

Is the SES light flashing when you are doing this? You need to count the flashes to determine the codes. The first code to appear will be "12", one flash, pause, two flashes, which will be repeated 3 times. This lets you know that you have successfully have sent the computer into its diagnostic cycle. After that there will be a pause and the stored codes will appear,( example Code 23 will be two flashes followed by three.)If there are no additional codes after it has flashed "12" during the first sequence, it will flash "12" again .