Sort of, it's multifunctional , it is used to store maps from you or a tuner, it can clear codes, monitor and datalog the way your engine is running etc. I'd look it up, cobb accessport. But my point is that's its likely the previous owner had a tune on the car thru an accessport(could've been open source but I don't want to confuse you) and that ap he used is married to that particular car. No car can use it unless its unmarried from that car. If the owner gave the dealer the ap when he traded the car in it helps you(in simple terms) but if the previous owner unmarried it, and sold it, and traded the car in, that's not so good. The car can be running on mods it's not tuned for, and that's a ticking time bomb. Sry I'm bad at explaining this shit, I'm no guru but that's the half assed gist of it.