Date registered: Mar 2005
Vehicle: '01-E320 & 02-ST2
Location: John 15:18-19
Mentioned: 0 Post(s)
Quoted: 35 Post(s)
There's lots of threads already on this; it all depends on what you want to accomplish. To me there is nothing more useful than a small hand-held device, plug it in, get your readings, clear codes if necessary, check readiness, etc. That's under $20 at Amazon (it was down to fifteen and change a couple of weeks ago): http://www.amazon.com/Autel-MaxiScan-MS300-Diagnostic-Vehicles/dp/B001LHVOVK/
If you want more, the interfaces to laptops and smartphones are a little more than that, but you have to have another piece of hardware; the tradeoff is you can do more, like gather live data.
For lots more you can also read and clear specific transmission codes through more complex interfaces.
Happy shopping, and good luck.
Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy; its inherent virtue is the equal sharing of misery. (Winston Churchill)