10 Problems Cars Can Diagnose By Themselves

Down the Drain
Some new BMW models have sensors that keep track of the drain on the car's battery. They'll even call you if you happen to leave your light on. Linda Patterson/Design Pics/Design Pics/Corbis

Sometimes when your car rats you out to the dealership, it's for your own good. Take, for instance, your habit of leaving your lights on until your battery is dead and you have to call your brother-in-law, the one with jumper cables, who is starting to hate you a little bit because you always call for help just as "The Bachelor" is starting the rose ceremony, and he loves that part.

Luxury car companies such as BMW also like "The Bachelor," and they want you to stay on your brother-in-law's good side, so they've got sensors to keep track of the drain on the battery. If things are looking bad -- again -- the car will, with its last electronic breath, communicate with the dealership rather than your brother-in-law. Then someone from BMW (someone who's probably not all wrapped up in "The Bachelor" at that moment) will give you a call to let you know that you need to shut your lights off.