Modern cars are packed with features and buttons whose purpose can be surprisingly hard to guess.
Modern cars contain countless features, switches, levers, and other elements whose purpose isn’t always obvious—especially if you’ve never cracked open the owner’s manual. A perfect example is a mysterious little button that can often be found beneath the dashboard of many American and Japanese vehicles.
Let’s imagine the following situation.
You’re driving down the highway when your car hits a fairly deep pothole. Suddenly the tachometer drops to zero, and the car starts slowing down rapidly. It becomes immediately clear that the engine has stalled. You pull over to the shoulder, stop, and begin trying to restart the vehicle.
You try again and again. The starter is turning the engine confidently, but the car simply won’t fire up. There’s no sign of ignition. The symptoms point clearly to a fuel-delivery or ignition problem. But a look under the hood doesn’t support that theory—no loose hoses, no disconnected wires.
So we’re left with two questions: What exactly happened? And what does that mysterious button in the photo have to do with it?
As is often the case, the answer is hiding in plain sight. Situations like this are fairly common with American and Japanese cars equipped with an inertial fuel-cutoff switch. This device is designed to shut off fuel flow in the event of an accident. In practice, however, it can sometimes trigger simply from hitting a pothole.
Yes—just hitting a pothole can set it off.
The “problem” can be fixed with that very button. In most cars it’s located somewhere under the dashboard, though there are exceptions. For example, in some French models the reset button is located under the hood. Pressing it resets the cutoff switch and restores normal fuel delivery.
Many drivers have no idea this button even exists—after all, who regularly checks under their dashboard?