selection criteria for ODB II code scanner

Kind of reminds me of the old Sears tool rating system, good, better, best; each level adds something that the other doesn't have..and that you'll wish you had after you get familiar with the tool. I've had a fairly sophisticated (for its time) Acton unit and it has paid itself back many times over. If you're just interested in knowing what the trouble code is get the cheapest one, if you want to know more than a few word definition of the code and/or view some of the data stored in the car's computer (freeze frame data) get the middle one, and if you want to watch the data change in real time as you drive get the best one, you'll have the most flexibility and the ability to print out data on your PC.

The price difference when readers first came out used to be ten to one or more, now at two to one I'd buy the one with the most features so that I don't have "buyer's remorse", but I'm a tech-toy guy. One more thing, if you like doing your own work then buy the factory manuals for your specific make, model and year, it will be an excellent adjunct to the scan-tool and help you to understand how all the systems play together.

N.B.- something that you can't do with most DIY readers is touch the ABS computer except to read out a trouble code, the manufacturers have rightfully denied access to it since fooling with that system affects the safety of the vehicle.

Thanks!, that was sort of my thinking as well. from what I understand more recent vehicles (from about 2008) have CAN, particularly the Japanese and European makes, but I'm still unclear whether it is an alternative communications protocol or if there is extra functionality over and above the standard OBD II protocol. I really have no interest trying to do anything to the ABS system other than read out diagnostic codes. But the real time data function could conceivably be quite useful. I actually have the factory service manuals for all three of my vehicles. I was lucky enough to find them floating about on the net at various places so I was able to pick them up for free.

I still ear a living turning wrenches. And I have 2 "readers" one is made by a company called Launch. It is the cheapest thing I have ever seen anyone use. It cost 49 bucks back in the late 90s. It has NEVER lied to me. It will read any codes that are active in the OBD II memory. I also have a $400+ Reader that can make coffee, and translate War and Peace into Latin at the same time.

One is just great for reading codes and then translating them into areas to start looking. One will allow me to freeze frame information at the exact time the MIL comes on. It will also allow the reading of individual sensors in real time. These features are great to diagnose what exactly is the malfunctioning part. And the expensive one is now 8 years old, and technology marches on.

My suggestion to you is to buy the cheapest unit that will service the vehicle(s) that you or your close group of personal friends own. After using it a few times, you will then see what features that you want are missing from it. Then you will be in a better position to determine how much additional technology you want. Good luck, and don't forget to look for used models.