Here’s Why The Check Engine Light Is A Horrible, Terrible Thing

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It happened on Thursday night. I went out to my car. I climbed inside. I turned the key in the ignition. And … nothing. Well, not quite nothing. A failed start. A check engine light. And an ominous warning message that said: TRANSMISSION FAULT: LIMITED GEARS AVAILABLE.

Now, this error message didn't scare me all that much, because my Range Rover has a history of these overly dramatic fault warnings. It's like a child who complains that there are monsters under his bed, murderous in their rage, terrorizing him as he sleeps, so you go and look, and the only thing under there are some old socks and enough dust to bury Pompeii for a second time.

An example: a couple of months ago, I got this warning that said "HDC FAULT: SYSTEM UNAVAILABLE" every time I started the engine. This scared me. I didn't know what HDC was, but by God, I wanted it to be available! So I took the car in, and do you know what the problem was? The battery was dying. It turns out this is the standard fault warning for the battery. I shudder to think what the error message might be if, for instance, the head gaskets start to fail. Maybe something like, "CYLINDER FAULT: PREPARE FOR DESTRUCTION."

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Anyway: undeterred by the failed start and the fatalistic warning message, I donned my Land Rover mechanic's hat, and I set about fixing the car on the roadside. In other words: I turned it off and turned it back on.

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You'd know what happened next if you followed me on Twitter, because I posted a picture of the aftermath. But basically: the car started right up. The transmission fault disappeared. But the check engine light stayed illuminated, proving yet again that my automobile of choice is approximately as reliable as a motion sensor faucet in an airport bathroom.

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And this brings me to the point of today's column, which is: the check engine light is the single stupidest warning light in existence. Stupider, even, than the "Low Tire Pressure" one, which is this little asshole warning light that tells you that one tire is low, and it's probably dangerous, and it could kill you, but you're on your own to figure out which tire it is. Imagine getting a call from the school principal, and he tells you that one of your children took off all his clothes during recess and threw a sandwich at the lunch lady, but he won't tell you which child until you show up at the school and stick a tire gauge in his mouth.

To help explain why I think the check engine light is so stupid, allow me to relate what happened when I called up the Land Rover dealer to schedule an appointment. Before doing anything else, the service advisor immediately asked one question: "Did you check your gas cap?"

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That's right, folks: the "check engine" light — a scary, yellow, brightly lit dashboard warning light that implies you have some serious fault with your car's sole method of propulsion — is most commonly caused by not twisting a 3-inch piece of circular plastic far enough.

But here's the problem: it's not always the gas cap. Yes, it's true that the check engine light is always emissions-related. But the check engine light can be any problem with the emissions system, from "tiny vapors are escaping through your gas cap" to "your exhaust system has sucked itself through the engine and the muffler is currently making its way through your cylinders."

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So what happens, when you have a check engine light, is as follows. The first time you see it, you freak out. "OH MY GOD!" you say. "A CHECK ENGINE LIGHT! MY CAR IS ABOUT TO BLOW UP!!" So you cancel all your appointments, and you tell your clients to find their own rides to the airport, and you tell your husband that he'll have to pick up the kids today, and you rush to the dealer, convinced your engine is moments away from a Hollywood-style explosion that will make the evening news. And you get there, and the mechanic plugs in his tool, and he charges you eighty bucks just so he can tell you that this scary, ominous warning light came on because you stopped turning your gas cap three millimeters too early.

So then what happens the next time your check engine light goes on? That's right, you guessed it: you ignore it. You go on with your day, your week. The light was nothing last time, you say, convincing yourself not to worry. I'm sure it'll be nothing this time. So you move on, and you put it out of your mind, and one day – when you have a few free minutes – you finally go in to the mechanic for an oil change. That's when he informs you that you should've come in sooner, because the check engine light is on, and your exhaust system has sucked itself through the engine and the muffler is currently making its way through your cylinders.

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The problem is that – by putting such a wide array of faults under the banner of one simple orange light – we've conditioned ourselves to ignore it. Your see the check engine light go on, but the car feels fine, and it sounds fine, and it acts fine, so your move on with your life, without regard for whether you have a loose gas cap, or a faulty oxygen sensor, or an adult hedgehog living inside your muffler.

As a result, I propose that we move away from the check engine light and towards descriptive warning signals that explain the car's exact issue. For instance: if you have a loose gas cap, a light comes on that says "LOOSE GAS CAP." If you have a faulty oxygen sensor, a light comes on that says "FAULTY OXYGEN SENSOR." And if you have a Land Rover, a light comes on that says "YOU'RE AN IDIOT."

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I can't be that much of an idiot, though. After a few days of driving, my check engine light turned itself off, proving that the best way to handle a check engine light is to simply ignore it. Shame about the hedgehog, though.

@DougDeMuro is the author of Plays With Cars. He owned an E63 AMG wagon and once tried to evade police at the Tail of the Dragon using a pontoon boat. (It didn't work.) He worked as a manager for Porsche Cars North America before quitting to become a writer, largely because it meant he no longer had to wear pants. Also, he wrote this entire bio himself in the third person.

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