Problems with the diagnosis port? on 1992 Lexus SC300

I have a problem in my car with the diagnosis port under the dash. I was wondering if it is a known problem or if it's fairly new? If you hook up a computer to diagnose the car it doesn't want to communicate with the car due to either a wire messing up or the car itself. This has happened twice with two different auto shops. It would be good to know about this.

Asked by for the 1992 Lexus SC300
run your VIN# to see if any recalls on this item. were there any modifications made to the engine(aftermarket parts)? has it ever been reprogrammed(chipped)?
Its purely stock. No mods on the car yet. There's a black box labeled "diagnosis" and theres a wire leading to it and where the wire connects to the box two wires are cut and all the connectors inside are fairly corroded. i have pictures if you want me to send them to you.
cut wires is never a good sign. given the corrosion build up and that some body tried to modify it(the cut wires), it will give you problems for diagnostic. best just to bite the bullet and have it replaced.