I have looked at about a half dozen 97-99 Bonnevilles. Toolgirl'* Fart Explorer needs to be phased out and I want her to have a decent DD for a couple of years, while every penny we have is going to tuitions.
So I got a scantool and got the expected aid in evaluating a car. And also got something I NEVER expected.
Good little tool. Shows me if a dozen or so sytem monitors are functioning properly. Then you can pick up any codes, particulary good if there is any "pending" codes. Then i can pick up some live data and freeze frame it, if something goes wierd. But that ain't the jazz.
Every time i pull it out and attach it, the salesman goes into a state of shock. Total. With some, it becomes a truth serum. They start telling me what'* "not quite perfect" with the car. This is recovery because, of course, they spent the walk to the car telling me it'* in the best shape of any car on the lot, even though it has years/miles on it.
Two just got visibly p*ssed off. I think it'* a control thing. I'm guessing they don't like the thought that the customer might not be a moron who can be manipulated. It annoys them that they can't conduct business as usual, which they are very, very good at.
The real ace is that they don't know HOW MUCH you can find out with the scantool. Which, in reality, is mostly some supportive info that can in no way replace a thorough visual inspection and test driving. But they don't know that.
It kinda' jumbles up their routine. Which is, no matter how polite everybody behaves, an adversarial situation.