The article straight up said that Google takes the data. The article may be wrong, but then that's the fault of MacRumors. We're not speculating beyond what the article explicitly states, or at least I'm not.
Actually, the articles don't. At least not the source article, which is the Motor Trend one. It lists the source as being "off the record", which means it's not an official statement representing any user agreements. It basically means it's hearsay.
Then they question the spokesperson for google, which is more than likely a not-very-technical person. She doesn't specify what, if any data, is collected, and that's probably because she doesn't have that knowledge (i.e... non-tech spokesperson caught a bit off guard by a random phone call). She knows enough to say that whatever it is, it's gonna be opt-in (not opt-out, that's an important distinction), and that they do use some information for safety... eg, lets not allow input while the car is moving, just like Car Play does, as well as every other DVD or GPS headunit is required to do... by law.
Access to OBD2 is part of the Android Auto protocol. As it is Android Auto has support for extended GPS antennas, directional mics, etc, etc, etc... from the car to make the phone work more seamlessly. This is what people are losing their heads over. I think it's a good part because it lets apps monitor and display info about the car if they so choose. It lets the device extend itself with the car's resources. Personally I'm REALLY hoping there's also a working group thats working to make some standardized set of API's that allows bidirectional access to control systems, at the very least for things like notifications from the car so they can show up on the Android Auto screen. Car Play will want/need this too.
The natural evolution of this is NOT just your phone taking over your car's media screen. We have HUD's and LCD's increasingly showing up in the dashes. If cars are no longer going to handle navigation (and lets face it, that's a very good thing), cars will need a language that lets phones access the secondary and tertiary screens for things like next-turn and lane change information. Luxury cars have TONS of options, and they're often obscured by terrible interior control design. The voice recognition stuff in luxury cars is neat, but atrocious. I'd much rather ask google to turn on my rear window defroster (a button which at the moment is a guess for me) than hunt on my dash or try and remember the weird command structure for my car late at night when I'm trying to drive with an opaque rear window.
Everybody here lost their senses over a poorly reported and unofficial blurb on a "what's cool about Porsche" article in Motor Trend. MOTOR TREND. This is the source... Motor Trend.