Though KSL has had its share of scammers, it's still better. The best you can do is have a trusted mechanic check the vehicle, pull the Carfax before you buy it (will show all owners, mileage, location etc.) and then I wouldn't pay cash unless it were under $1k. I'd use a cashier's check to create some kind of paper trail as they will have to show ID to cash it. Either that, or get a photograph of their ID and their face when you buy it. Perhaps even a picture of the vehicle they are driving when you meet.

If the vehicle is heavily discounted, that's a red flag. Most times you should be able to judge if it's a shady deal when you meet but obviously there are some really good con artists out there.

As for the computer hack, I'm sure they just wiped the codes. It takes something like 20 miles of driving before they show up again. I have a code reader that can wipe the codes. They aren't expensive, but they can be handy. For example your check engine light could come on simply because your gas cap isn't completely tight. It's nice to be able to wipe a code like that to see if you fixed the problem. Plus, knowing what the codes are is good so you know if it's safe to drive. Most of them are related to emissions though.

Unfortunately for you, an ounce of prevention is worth a pound of cure. I'm not sure what you can do at this point having already been scammed.

I know on KSL if they suspect or have evidence of fraud, they will add an alert to the ad and other ads by that user. I don't know if CraigsList does this but if not, one more reason not to use it.