Tips From A Tech: So You Want To Buy A Scan Tool? -

Tips From A Tech: So You Want To Buy A Scan Tool?

If the title of this column caught your eye, that means you are most likely interested in purchasing a scan tool of your own.

If the title of this column caught your eye, that means you are most likely interested in purchasing a scan tool of your own. You’ve probably also noticed that the available choices can be overwhelming if you’re not sure what to look for.  Let’s look at some of the features and functionalities that are out there, so you can choose the right tool for the job, without breaking the bank!

How will you use it?

Are you just interested in seeing why the check engine light is on?  Do you need to see live or freeze frame data to aid in your diagnosis?  Or, do you need to be able to interrogate multiple control modules (PCM, ABS, airbag, etc.) with bi-directional support?  If being able to read and clear trouble codes, determine MIL status and check readiness monitors is all that is needed, a basic code reader might be a good option.  However, if you need something more robust to be used as a professional tool, let’s read on!

Generic vs Enhanced OBD2? 

Generic powertrain codes are codes that are common to all vehicles since 1996, and begin with “P0”.  These codes are stored in the computer when an emissions fault is realized by the PCM.  Most of your basic scan tools will easily be able to interpret these codes and give you basic, but useful data.  However, the OBD2 system was designed to allow manufacturers to go “above and beyond” the generic codes.  These manufacturer specific codes begin with “P1”.  To access these codes, a more powerful tool may be needed.  


I would highly recommend finding a tool that can be updated.  My personal scan tool uses my iPhone as the interface, and is updated on a regular basis, free of charge.  Since updates on some scan tools can be expensive, make sure you know the cost (if any) associated with regular updates.  That alone can be a deal breaker!

One-way or Bi-Directional Communication?

One-way communication is the ability to read the information from the PCM without being able to “talk back”.  Look for a scan tool with bi-directional functionality if you will be using it professionally.  Being able to command certain vehicle functions for diagnostic purposes is very important for professional use.  Just recently I had to reprogram the VIN number of a vehicle into the PCM to turn off multiple dash lights!  A code reader or basic tool would not be able to perform that function.  

If nothing else, remember that the best feature of any scan tool is YOU!  Without having the skill to interpret its data, even the most advanced tools will not help you in your diagnosis.  Lastly, don’t get caught up in the features of the tool, but rather determine what YOU need it for.  In my experience, knowing how to interpret a basic scan tool will provide more than enough data for personal use.  The cost of a tool that is capable of bi-directional communication and enhanced data would be much better suited (and justified) for professional use.  

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