I don't think you need the OBDII. Just put your headlights etc. on so there is a draw to pull in the alternator, and check across the pos and neg of the battery. It should read approx. 14.4v. If it doesn't the alt. is probably bad. If you are specifically asking if it can be checked with OBDII, I don't know.
Thread Hijack - I finally got to talk to the Alt. shop that used to do much of my business starter/alt. work about how to test an alternator for the amount of amps it puts out (Mean Green etc.) They told me to hook up an amp gauge between the post on the alt. and the wiring. It must be tested under a very large load - equivalent to the alt output. He said they use something called a Carbon Pile (sounded like something like I had removed from my Carbon butt) to load the alt. for the test. I see Northern Hyd. sells such a thing, 500 amp $299.00. He said he would be glad to test the Mean Green for me but didn't think much of an alternator in such a small case supposedly putting out such a large amount of amps and lasting very long.
That sounds like http://www.fluke.com/products/home.asp?AGID=0&SID=0&PID=9319. (is that right?) I have one for the fluke 88, and need to try to use it in the am. Heck dude, mine just took a dump I think today. Figgers, had tonto riding shotgun and wasn't happy about leaving my diet coke to spoil in the sun.