When I plug my V2 into my truck it does not power on, I can see the green light barely flicker when plugged in. Once I connect it to my laptop it powers up fine, I can flash tunes and log with it fine as well.
i would say check your cig. fuse. but you say it can read and flash fine...
so maybe your OBD 2 cable got a bad wire ( the one that supply's power) what do the connection points look like dirt greese.. ect...
jsut some thoughts
As above, the cig fuse seems the likely culprit except that you say you can flash. I'd check the fuse anyway, then try connecting to another vehicle to determine if it's vehicle related or FlashScan/OBDII cable related.