Just to stay on top of things Jammie, my last post was to hopefully help you in great way. To clarify, if the pinout on your connector is exactly like the 1st diagram, you DO NOT need to purchase a scan tool. You will be able to just bridge terminals 5 and 6 and turn the ignition to on and the Check Engine light will flash you all the codes. If you need help deciphering the flashes just ask.
If your connector is not exactly pinned-out like the 1st diagram, you will have to locate a scantool. Please don't try jumping pins on any other connector because you will fry the ECM :p
GM didn't run a test wire to any other 16-pin connector that I know of for OBD1, and its been so long I cannot remember the color codes or the test terminal on the ECM right off hand. Where there'* a will there'* a way, and if you really absolutely had to, you could get those codes without a scanner, but the steps to located the wires needed is probably beyond the scope of how much energy you want to spend on this car :p
Find the 16-pin connector under dash, drivers side. JammieM, which pinout do you have? X denotes unused terminals.
OBD1 with 16 pin connector.
\ X | X | X | 4 | 5 | 6 | X | X /
`\9| X | X |12| X | X | X |16/
An OBD1 variation found on a 95 LeSabre and 94 Park Avenue (no self test)
\ X | X | X | 4 | 5 | X | X | 8 /
` \9| X | X | X | X |14| X |16/
\ X | 2 | X | 4 | 5 | 6 | 7 | X /
`\X|10| X | X | X |14|15|16/
If its the 1st, her ECM can be definitely read by just jumping 5 (ground) and 6 (test)
And enough of this silliness about hybrid OBD1/2. OBD1.5?
The fact of the matter is that GM just began to roll over their entire lines to OBD2 in the '94 model year. Very few cars rolled off the line for 94 with OBD2. A very simple way to tell is if your computer is in the passenger cabin of the car, it'* OBD1, if its in the engine bay, its OBD2.
When the assembly lines started to run out of 12-pin OBD1 connectors, they just started using the new 16-pin connectors for the OBD1 wiring. Thats all. The problem (most likley), is far too many lower hotshot wannabe super engineers (like me) were involved with something as simple as a change like this. I have seen OBD1 cars with 16-pin connectors wired in no less than 6 different ways. Thank you GM Standards.
I apologize for the long post. I was bored