There are a number of different ODB2 scan tools out there, some PC based, some standalone units, some more for tuning and some more for diagnosing problems.

What are the different features that these devices provide? What are the pros/cons among different models? Is there one or two that "stand out from the crowd" as being the better ones?

Professionally I work with computers which diagnose Commercial vehicles (J1587, J1939 etc) so I'm somewhat familiar with how they work, but I'm totally new to the passenger vehicle space.

This is for my personal use, I have a few Nissans and a Subaru. Price wise I'd be interested to hear what the ranges are for a good one. I've seen them anywhere from $80 to several hundred.

4 Answers 4


If you're looking for personal use and already have access to a laptop computer, I'd highly recommend getting a PC (or Mac, if that's what you have)-based one. You buy the hardware, generally for $100 or less (I recommend the units from ScanTool.net - the less expensive ones are fine). The biggest advantage is that you can start out with the free software that comes with it, or download free stuff from other sites. If you find that you need more features, manufacturer-specific PID access, etc. you just buy upgraded software as needed. A PC-based scan tool will also allow you to do fancy stuff like detailed data logging, realtime graphs, or a "dashboard" display of important PIDs on the laptop.

  • I am also in the market for an OBD II reader and have come to the same conclusion that a PC based solution is the way to go because of all the added features you get, and the unlimited possibilities based on what software is written for it. I have also come across a couple of open source projects at sourceforge but unsure of how well they work.
    – Tone
    Commented Jun 4, 2011 at 20:44

I cannot answer all of your questions, as my experience is only with one OBD II scanner. I can give you the feedback that I've been using the very basic Actron CP9125 for years, and it has served my purpose of reading CEL codes (and resetting them) very well, on a number of different Japanese import cars.

The Actron CP9125 can only read codes (and it comes with a paper booklet that translates most of them into brief descriptions of what has triggered them). It is not a device for datalogging or tuning the vehicle via adjustment of fuel maps, ignition timing maps, or rev limiters.


I've used a couple. I've got an old Actron that works just fine (ISO only though in whatever model it is). I've also got Alex Peper's PC based software (w/tri-mode cable) and that works great.


The best of the best is a software product called CANoe by Vector along with a CANCaseXL type hardware device.

A good runner up is the NEOVI Fire or ValueCAN from Intrepid Controls and their Vehicle Spy software; Vehicle Spy software, however, is total garbage! It crashes and is extremely buggy for anything beyond simple reverse engineering which it's fairly good at.

These software packages "spy" on the CAN bus and dump the data to a scrolling display. They all basically allow the loading of a database file, called a DBC file, that decodes the CAN data into human readable information.

The DBC files go by different names. For example, GM calls theirs the "Global A platform"

ELM chips and ScanTools products are very amateurish. They don't, for example, have the ability to run the full ISO14229 or have the ability to be augmented with database decodings.

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