Choosing a scan tool can be a challenging task.  Scan tools can range in price from a few hundred dollars to several thousand dollars.  Here's a few thoughts to consider if you are in the market for a scan tool.

What is a scan tool?

A scan tool is a device used to interface with the car's onboard computer systems.  These systems can be in control of the engine and/or transmission (powertrain), safety systems like antilock brakes and traction control (chassis systems), or passenger convenience and comfort systems like air conditioning, power windows, and entertainment systems (body systems).  This is a short list...today, there are numerous systems incorporated into a modern car that are controlled by some type of computer module...but you get the idea.

Most aftermarket scan tools will not access all of these systems.  None will allow you to reprogram any of these systems.  So, the first question to ask yourself is "Just what do I want to be able to do with my scan tool?"

If you are a professional tech, then you know that there is no substitute for using a factory level scan tool.  Having the same tool as the dealers allows you to access all the information, have all the same bidirectional controls, and all the same reprogramming capabilities as they do.

The only problem is the cost.

As an independent technician, I work on everything from Acura to Yugos.  Unfortunately, there is no ONE tool that allows factory level coverage on all models.  So the cost can be prohibitive.  If you are a professional tech, then consider what you have the greatest need for.  Do you work on mostly domestic, Asian or European?  Would one or two factory level tools provide you with the coverage you need for the vehicles you service most often?  Do you run into the need for body and chassis access that you don't have already with your aftermarket equipment?  If your work is primarily powertrain related, you may be able to use higher line aftermarket tools to accomplish the same thing at a significant difference in cost.

Let's take a look at some choices.

Factory level tools, like the Tech 2 pictured, offer access to all OE data and controls, including reprogramming of all modules.  However, these tools are not cheap and often require subscription fees to keep them current.  And as I mentioned, there is no ONE tool that covers all.  For example, just to cover the domestic manufacturers, you would need the Tech 2 for GM products, IDS for Ford, and StarScan for Chrysler.  These last two are PC based tools, but we'll talk about that more later...including an aftermarket program that provides great coverage at an affordable price.

There are several choices available in the aftermarket for scan tools that are increasingly more competitive with the factory level tools.  Many of these tools allow access to the same modules and sytems, with many of the same bidirectional controls.  None, however,as of this writing allow reprogramming and for the professional, reprogramming of various systems is becoming more and more of a real need.

The two most popular seem to be the models offered by Snap-On and the OTC Genisys.  The major drawback to both of these tools is the cost of updating them.  These updates can be several hundred dollars a year, less than most factory updates, but a significant cost nonetheless.  For the professional, it's a cost of doing business.  For the DIYer, there are better options yet to come.

When I worked as a dealer technician, I had access to factory level tooling.  But shops don't keep a scan tool in stock for each tech...usually there are only one or two.  So it's often easier to keep a cheap, basic scan tool in your own toolbox that will allow you to access Global OBD information and codes.  This level scan tool is also ideal for the DIYer who just wants to maintain their own car.

There are several choices available for these tools.  My personal choice is the OTC Nemisys.  The Nemisys is the smaller brother of the Genisys and uses the same database, without all the bells and whistles...and cost...of the more complete Genisys.  Snap-on also makes a more basic version of their scan tools, and you can get more information by contacting your local Snap-on dealer or visiting www.snap-on.com

No matter if you are a professional or DIYer, the future in scan tools is in PC-based diagnostic software.  Many factory programs are now PC-based, and there are a number of aftermarket programs that are very capable.  Again, it's a matter of cost and what your individual needs are.

If you are a DIYer looking for just generic information, or just want factory level coverage for your vehicle, consider the AutoEnginuity software offerings.  In addition to Global coverage, the basic scan tool includes the SpeedTracer software, great for the home tuner. 

For the professional, the ProLine bundle is an alternative to factory level tooling for the professional, and a much lower cost...both in initial purchase and in updates.  The line of AutoEnginuity software is available right here at AutoServiceTech. 

Choosing a scan tool comes down to your individual needs, preferences, and budget.  Ideally, as a professional, you would want factory tooling and I certainly won't discourage you from that end.  But as a working guy myself, I know that that isn't always economically feasible.  The next best choice, in my opinion, would be found in one of the various PC-based platforms.  After that, the high end aftermarket tools.

For the DIYer, a simple Global OBD2 code reader would suffice for most needs.  The AE Basic package is an inexpensive means to use your personal PC, Palm or PDA as a scan tool and tuning tool.  Should you want factory specific information, it can be easily added.

Whichever you choose, take the time to do your homework before you spend your money.  As a professional, my tool expenses are not judged just on cost, but on how much the tool will help me make a living.  Make sure the scan tool you invest in will spend most of it's time working for you, and not collecting dust in your toolbox.