Yet another question on our new-to-us 2012 DB9:

This weekend the "Emissions Service Required" message came up. I figured I hadn't tightened the gas cap all the way or something, as that is a usual culprit, so I checked it, and a few starts later, the light went off on its own.

But, while driving a bit after that, on it came again.

Possible culprits? The car was just serviced by AM and no issues were noted at that time.

Also, what ODB II reader do you guys recommend? This one gets a lot of positive Amazon reviews, and the bluetooth linkage to Android appeals to the geek in me:
Any reason to get something other than that one?

 

I use this one
http://gopointtech.com/
Has been great and allows for data logging with my racerender software. Always links quickly with my phone.