Problems with the diagnosis port?

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.