OnStar recently showed a prototype of a new service at International CES that operates from the driver's cellular phone, Twice reports. As yet unnamed, the service lets users remotely lock and unlock the doors of the car, remote start the vehicle, flash the parking lights and offers other concierge features directly from an icon interface on the user's cellular phone. In addition, the system can remotely run car diagnostics from the phone to check oil life and tire pressure, the company said. The system does not send out alerts for these features, but lets the user check these features remotely, as desired, from anywhere within his cell phone service range. The feature was announced during a CES keynote presented by Rick Wagoner, chairman and CEO of General Motors. If a customer is at the airport and can't remember if he locked his doors, he can take out his cell phone and lock them from any distance, said Wagoner. According to Twice, OnStar also said it will deliver its Stolen Vehicle Slowdown service, first shown last year, by mid-2008. The service can slow down a vehicle in the act of being stolen.