How do you retreive the computer codes for a 1994 olds cutlass supreme All the testers out there are not applicable to that year?

OBD-II (On Board Diagnostics tool version #2) became available on cars after 1996. Prior to that time OBD 1 was implemented, but finding a reader for this is available on line. The cost is around $50-$60. It is cheaper to take it to the dealer and ask them to read the code for you. You'll probably pay $20 to the mechanic for the time spent.