In a press statement issued on January 31, General Motors announced that its OnStar call centers receive more than 150,000 calls a day. That equates to almost two calls per second.

Yet for the past few days, some of the more than 6 million users of the telematics service have been unable to use it.

Some OnStar users reported very long waiting times while others that they received automated messages to call back later. The problem, as told by OnStar spokeswoman Cheryl McCaren on FoxNews, was caused by an upgrade to the operating system on Sunday, February 12, which affected non-emergency “Blue Button” services.

Although the system, which has been on and off, is back on line, McCaren admits that it still has problems with registering new users or reactivating previously dormant accounts.

The OnStar telematics system is currently available in more than 30 models in GM’s range, with annual subscription costs ranging from US$199 to US$299. The system comprises of features such as Automatic Crash Response, Turn-by-Turn Navigation, Stolen Vehicle Location Assistance, one-button access to emergency and roadside services, and hands-free calling, including Bluetooth connectivity.

Since spring 2011, it can be installed in most non-GM vehicles as well. All it requires is the replacement of the center mirror, where the system is located. As a matter of fact, GM did not pass on the opportunity to gloat over the recovery of a stolen Chrysler 300C, though the system was apparently working at the time…