GM Halts Access to Vehicle Data


Since October 13th,, a popular site for tracking efficiency statistics for the Chevrolet Volt, no longer has access to Volt data. was started by Volt owner Mike Rosack in April of 2011, and is not affiliated with GM.  It allows Volt owners to voluntarily sign up to have their Volt’s mileage and efficiency statistics tracked online, and viewable to anyone who visits the site.  This is done by providing their OnStar RemoteLink credentials to VoltStats. Data can only be read, since a four digit key code is required to send the vehicle other commands, which does not collect.  Vehicles are only identified by the last 6 digits of a person’s vehicle identification number, as well as an optional nickname for their Volt.  Volt owners can earn trophies on the site for feats such as the longest distance traveled without using gasoline, number of miles on a single tank of gasoline, and number of electric miles driven in a day.

There are a few statistics that cannot be tracked by, such as what it feels like to experience a silent ride with instant torque and no shifting of gears.  However, that can all be answered with a test drive, chatting with a current Volt owner, or realizing that the Volt ranks the highest in owner satisfaction of surveys conducted by both Consumer Reports and J.D. Power & Associates.

This Histogram Charts the Percentage of Days That a Volt has Driven a Given Number of Miles on Electricity Only (Green Bars) and on Electricity Plus Gasoline (Blue Bars)


As of this month, has over 1900 Volt owners signed up to have their vehicle data tracked, or a little less than 10% of all Volts sold thus far.  This is more than enough vehicles to obtain statistically relevant data about the entire Volt “fleet” and, so far, the numbers are impressive: all Volts signed up have driven an average of 129 miles for every 1 gallon of gasoline that has been used.  Furthermore, over 70% of the mileage put on these Volts have  been using grid electricity.  These impressive numbers have been referenced by many people to show how successful the Volt-concept really is at reducing gasoline usage and meeting the majority of commuting needs with grid electricity. is arguably one of the best marketing tools that GM has for would-be buyers of the Volt to prove how great the car is for reducing gasoline use and operating primarily on grid electricity.  So, why in the world would GM want to prevent from continuing this free marketing for them?  I emailed Mike Rosack, the creator of, to see what information he has been told: recently stopped displaying new data.  Why did this happen? Owner Map Shows Locations of Volts Tracked by Town

I’ve never been an official partner of GM or Onstar, but they knew about my site and had no problems with the usage until recently.  On Saturday, October 13th, GM contacted me to inform me that they had to shut down access to the credentials I was using to pull data from Onstar, citing vague security concerns.

How did the API get disabled?  Did they just tell you to stop querying everyone’s cars, or did they somehow block those queries?

They blocked the service credentials I was using to authenticate – the current version of the RemoteLink app uses different credentials.  However, it’s fairly clear that I’m not supposed to try and get Volt Stats back up and running without their blessing.
Does GM realize the significance of the data that provides to its potential consumer base as well as naysayers on the technology?

I think so.  They were very clear when they notified me last Saturday that they realized the service was important to a lot of Volt owners, and that they were looking to get the site up and running again as quickly as possible.  I think it’s been a great asset to GM and the Volt – I’ve heard from many owners who said it helped them make up their mind to purchase a Volt.

Does GM intend to allow access to the data for VoltStats again in the future?

I haven’t heard anything from GM or OnStar this week that makes me doubt that they’re trying to figure out a way to get the service restored, but I haven’t heard much from GM or Onstar this week, period.  I believe this is much more of a legal issue than a technical issue at this point.

Is there an estimate as to when the data may be back online?

If you had asked me last Saturday, I would have said early this week, but that obviously wasn’t the case.  At this point in time I really have no idea when service will be restored – it could be Monday, it could be a couple of weeks.

Blue Volts Look Sharper Than Black Volts (Sorry, Jay)

So for now, the most comprehensive public dataset of Volts on the road today continues to be devoid of data updates from OnStar.  As one of many Volt owners, I hope GM is able to restore site access quickly, for their own benefit, as well as for all the Volt owners that have signed up for the service.  It is an amazing treasure trove of data for current Volt owners, and also helps prove that a 40-mile extended range electric vehicle can significantly reduce gasoline usage while providing limitless range.

UPDATE, 10/24/2012:  GM has released some new details, covered here.

Categories: Chevrolet, General


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8 Comments on "GM Halts Access to Vehicle Data"

newest oldest most voted can only help increase Volt sales so I’d be surprised if it isn’t back up and running within weeks….. how else would we know the top Volt driver gets 15,000 miles per gallon…


‘how else would we know the top Volt driver gets 15,000 miles per gallon…’

and has wasted a pile of cash lugging around all that unused metal. 🙂

Voltstats, more than anything, has proved that GM really did their homework on this one. You could easily see that 40 miles was the sweet spot. Much more, and there is diminishing returns. (Now when will GM complete their “bonus assignment” and make the MPV5, or better yet, a 7-seat SUV?)

Looks to me like GM wants some of that web traffic. If there isn’t a big backlash from Volt owners look for an announcement that GM will be providing stats on their own web page.

This is so silly and annoying — OnStar is just shooting themselves in the foot. volstats like tracking is the only reason I care about onstar.. If its not usable I’ll probably just cancel it now. Well, maybe they don’t want mike to reimplement a new version, but they are kidding themselves if they think the volt community cannot redo something similar with the new protocol — the Volt owners have man high-tech early adopters. Since I can see all the data needed on my android/iphone, and most of it via a web-browser, maybe time it is time for a new design that uses scripts to download the data myself and then centralize them for comparison And if they are worried about the traffic, a better P2P system, where users run the script on their own machines (and then report it to a central site for tracking), would allow users like me, to poll 12 times a day instead of voltstats 2. I was already tempted to do this when they cut back from 4 to 2 times a day. I guess GM/Onstar does not get the point of user access and sharing data. They need to look at the… Read more »

So we are left with the useless The site that took over a year to even try to report usage data, and then promptly stopped working once it had started?

The MyVolt page never reports any electricity usage data for my car, though it does have the mileage number up now. (I just went to check for the first time in several months, but only because VoltStats has been cut off by Onstar…)

Why does Mike need GM’s blessing? Seems like Volt owners should be able to decide for themselves how to share their data.