The OEM scan tool equipped with many features probably will be your best choice

Automobiles have a sensor that will light up on the dash when an engine needs to be serviced. This light requires that your vehicle be connected to an obd scanner. This tool, when plugged into the circuit board on a vehicle, will display engine codes that diagnose the problem.The OBD scan tool operates to the specific year, make and model of a vehicle. The auto scan tools are equipped with many features. This tool is purchased based on the tasks to be completed, the pricing and the features that you need.

If you are a professional technician and specialize in a single import nameplate, for example, the OEM factory scan tool probably will be your best choice. Factory scan tools generally provide access to all the diagnostic trouble codes (both “generic obdii” and “enhanced”), all the on-board test procedures, and usually most of the on-board electronics beyond engine performance and emissions (such as ABS, air bag, suspension and so on, if these systems have scan tool diagnostics).
ADDITIONAL REQUIREMENTS Something else to keep in mind is that an auto scan tool by itself cannot fix anything. It takes a brain to operate and use the information provided by the tool. That, in turn, requires an understanding of the vehicle systems you are working on, access to current service information, technical service bulletins and electrical wiring diagrams.If you do not know how the system works, what causes a code to set, or how a particular sensor or circuit is wired, how are you going to fix the fault?

You also cannot rely on codes alone to identify all problems. Many problems never set a code. Some codes can be misleading because of the combination of circumstances that caused them to be set. Other codes may be false codes that never can be eliminated by normal repair procedures. You may have to reflash the computer to fix the problem.
The best advice here is to always check for TSBs, whether you find any codes or not. In many instances, there will be a TSB that covers the problem and will save you hours of frustration.In conclusion, the more time and research you put into choosing a car diagnostic tool, the better satisfied you will be. Check with your equipment suppliers or the sources listed with this article for specific product models, features and prices. Spend some time on the Internet researching the various alternatives. Do your homework and you will find the tool (or tools) that are right for you.