Finding 10 problems a car can diagnose on its own is actually a lot harder to pin down than you might think. Now that we're firmly in the twenty-first century, a better question might be, "What problems can't a car diagnose for itself?" Other reasonable questions: "If my car knows so dang much, why isn't it as cool as K.I.T.T.?" and "Are cars actually our robot overlords?"
Cars today are surrounded by sensors -- they're in the engine, the tires, the reservoirs, the windshield, the electrical system, the seat, your brain ... wait. No, not your brain. Probably. All these sensors and the systems that keep track of them are known as on-board diagnostics, or OBD (not to be confused with deceased rapper ODB).
The point is that vehicles of all kinds can keep track of their own health. The problem often comes when they try to communicate their information with the driver. Like a cranky baby who cries no matter what is wrong, from an ingrown fingernail to Hantavirus, cars will light up that "service engine" light in the dashboard for nearly every problem from a loose gas cap to an engine that's about to explode.
And that's where the diagnostic trouble codes come in. The car's computer spits out a code that can only be deciphered by a reader, which is usually in the hands of your mechanic. He'll probably tell you your gas cap is loose, and you'll want to kick in your own windshield to teach the car a lesson about what's important in this life. Robot overlords indeed.
But there are specific things a car can diagnose and share with you in plain English. Here are 10 of the most common and most interesting, in no particular order.