If you are unab,le to enter OBD1 comm with a scantool Id suggest trying it with in analog mode next. The scantool is like a PC, takes alot of circuits and software and output stability for it to count its 1s and 0s in correct positions and make data or code information out of them for a scantool.
However you can get it to count codes with a meter or testlight just fine. There are videos available on the procedure all over the web. Basically, you want to ground the grey STI single wire lead (recommend use a testlight, in case of shorts the load of the bulb will act as current limiting protection for the circuit). The Grey STI lead is next to the vehicles DLC data link Connector underhood. The connector is usually near a hood hinge, near the battery, or in one of the front 2 corners, and will usually be black with a cover over it marked EEC IV TEST and will have a large 6 pin connector and a small 1 pin connector snapped into the cover. Heres a picture.
SO, find that, connect a ground to the STI input wire, then turn on the key and watch the check engine lamp. If it starts flashing, you will get your codes by counting flashes. If it DOES NOT, now you will have to start diagnosing control circuit inputs. All powers, grounds, memory leads. It can take awhile and use of a breakout box and ECM wiring pinout and diagram is strongly recommended for time saving..