There is a subtle art to listening to your vehicle. Long before a car breaks down on the side of a busy highway or refuses to start on a rainy morning, it usually gives you quiet hints that something under the hood is wearing out.

If you were to strip down an engine while it’s running, you’d see hundreds of precision-engineered metal components sliding past each other thousands of times per minute. The only thing keeping those metal surfaces from grinding themselves into fine dust is a microscopic film of oil thinner than a strand of human hair.

We’ve all been there: you’re driving down a straight highway, you briefly ease your grip on the steering wheel, and immediately feel the car drifting toward the shoulder. Or perhaps you hit a nasty pothole last month, and now the steering wheel sits slightly crooked even when you're traveling straight.

There was a time when fixing a car involved little more than a set of wrenches, a keen pair of ears, and a bit of trial and error. But pop the hood of any modern vehicle today, and you’re looking at a sophisticated network of computers on wheels.