This handy little bugger is !!!!
You can only beat the price of this by going to Autozone and getting your CHECK ENGINE light scanned for free.
I bought two on Amazon for $20.00, and then downloaded an android app for my Galaxy S III smart phone called "Auto Check" OBDII reader. (I'm sure there's an app for the i-Phone drones out there too.)
Now I know exactly what the code is as soon as the Engine light comes on, can also get Engine Stats on the fly and load it from my phone to my computer.
Tech at it's best!