A CarMD gadget showed off at this week's Consumer Electronics Show in Las Vegas is tapping into auto technology to help people keep mechanics honest.
CarMD plugs into ports that are standard in 1996 or newer model cars, then quickly analyzes data from the hundreds of sensors built into today's increasingly computerized vehicles.
A green light indicates all is as it should be, while red or yellow lights warn of car problems.
The gadget is then plugged into an Internet-linked computer so it can go to a CarMD website to fetch information about what is wrong and how much it should cost for repairs.
"It is basically empowering you with information that your mechanic normally would have," Kristin Brocoff of CarMD told AFP while demonstrating the device.
"It is peace of mind. People still don't trust mechanics. When it comes to fixing your car, we are giving you a second opinion in your back pocket."
CarMD is priced just shy of 100 US dollars and there are no subscription fees or hidden costs, according to Brocoff.
Explore further: Tech review: Nikon's P900 takes the term 'super zoom' to a new level