A new service from General Motors\u2019 OnStar subsidiary that performs remote diagnostics on vehicles and sends the owners reports once a month could eventually make it easier for car companies to use this data to prevent manufacturing defects.The diagnostic tests are enabled through wireless communication with a car\u2019s computer system. When the car is in operation, data about the performance of the vehicle\u2019s critical parts and processes, including air bags, antilock brakes and the engine, is transmitted from the car\u2019s main bus to an onboard computer that sends the information to OnStar. OnStar then processes the information and sends an e-mail to the vehicle owner, who can use it to plan maintenance and repairs.The service comes with an OnStar subscription and is available on most 2004 or newer GM cars. For model year 2006, more than 50 GM models will have OnStar as an option or as standard equipment. Currently, the service is meant primarily to attract and retain OnStar customers, according to company executives. Down the road, auto industry analysts say, the technology could provide a new way for GM\u2014and the auto industry generally\u2014to gather data about how vehicles perform and build better cars. \u201cOnce we do get the data back in office, there is an opportunity for GM to understand what\u2019s going on in the field,\u201d says Steve Samolinski, OnStar\u2019s service line manager.Until now, adoption of prognostics\u2014the ability to identify impending system failures by analyzing vehicle data\u2014has been slow, according to Joe Barkai, program director with Manufacturing Insights (owned by IDC, a sister company to CIO\u2019s publisher). Car companies have had to rely instead on dealers to pass on data they collect when they do repairs.Although not very expensive to implement in comparison to OnStar, remote diagnostics was not a priority for auto manufacturers when the economy was poor, says Mark B\u00bfnger, an analyst at Forrester Research.Now, that\u2019s changing.