TECH 2 scan tools work with GMs from 1991- 2013
OBD1 is everything before ’96!
If the menu is in the Tech2 for ’91 then that hints that all you would need is the correct 16 – 12 connector/adapter and also likely a provision to power it with the adapter. OBD2 is self-powered from the DLC, OBD1 ain’t. ’94 & ’95 would work without the adapter, they’re 16 pin DLC with pin 16 being B+.
I’ve used my “REAL” Tech 2 Scan Tool with ’95 but not Corvette, compared to my Tech1 on the same car I did have some contradictory comparisons that I couldn’t explain. I don’t recall them now but it did confuse me for a time. I put a JY ECM in a ’95 ParkAvenue for a fellow to resale and it ran well so I worried NOT about it.
FYI, There is a Tech1A OBD1 to OBD2 interface that lets the Tech1a work fine with 96.
I have done it multiple times, you MUST have a Tech1A with correct mass storage module to install a new PCM or CCM to program key fob resistance, mileage , vin info ,LT1 or LT5. You have 100 miles after install to program the module or it becomes non programmable. (this pertains to new or reman module, used module is just what you get and is non programmable)
Edit: The manual says it should work with the OBD I connector:
2005 Tech 2 User’s Guide VI – 15
If not properly grounded, the CANdi module will appear to be defective when it is not. The Professional Diagnostic Tool CANdi module will fail due to improper grounding if you use the 16-pin DLC (J-1962) connector and power the
Tech 2 from an AC/DC power supply. The adapter you use must have a GM part number. Although PVI
adapters are similar to GM adapters, they will not work with the CANdi module.
CANdi Module Troubleshooting Guide
If a CANdi module is not functioning properly, please perform the following tests:
Make sure the CANdi module is properly grounded by connecting to a vehicle or by using the 12-pin
ALDL connector, which has the signal and chassis ground shorted.