The $50.00 scanner will only read the code # to you. The more expensive ones will let you read live data as the engine runs down the road. You won't always get a code with a problem. We work on a lot of Ford Powerstroke Diesel trucks. A cam position faliure won't always set a code, but the truck won't run. Looking at live data can help solve the problem.

Some auto parts stores will scan it for you for free. That is if it runs to get it there.