I emailed GAP and asked them what I needed to do to read generic codes on a Rover I was looking to buy other than one that is registered (I was far enough long in the purchase of the car that I would have invested the $80 to add the VIN just to know everything about the car).
They said it would read generic codes on any car but the "advanced" features were locked to the registered VIN. Not sure were the "Basic-Advanced" line is but......
I have used it in on other Rovers sitting on the dealers lot that I am looking to buy.

When show the dealer that you read the old or pending codes and got "47" different items that need correction, it is alway a good starting point for price negations.
I would just plug it in and see.

Hope this helps
Jeff

 

IID allows reading/clearing codes and displaying live values for any VIN. This is extremely handy.

You can’t change CCF, flash firmware, program keys, nor calibrate the suspension (and stuff like that) without a VIN license.

 

I assume the question about other cars was to mean other cars, not other Land Rovers.