Handling the Glare of Multiple Warning Lights

Dear Car Talk

Dear Car Talk | Mar 29, 2018

Dear Car Talk:

I'm a Southern belle, and I need some help. After 55-plus years of marriage, I have learned a thing or two about cars. But I don't know the answer to this question: Can a check engine light and a flashing cruise control light mean imminent doom? I love driving my '07 Subaru Outback, and find that it handles well and is easy to get into and out of (if you hold the door open with the toe of your shoe).

I read something on the internet suggesting that this is a common thing for the Subaru, and that it will heal itself in a few hundred miles. Should we go happily down the "it'll fix itself" trail, or should we think about trading it for a newer model? -- Belinda

Wouldn't it be great if the check engine light also displayed the dollar amount it's going to cost you? I'm going to work on that invention. The answer to your question depends on your definition of "imminent doom," Belinda. Is a few hundred bucks imminent doom for you? No? OK, how about $1,500?

These two lights could be caused by a single problem. For instance, if your vehicle speed sensor or your throttle position sensor is bad, the check engine light will come on, and the cruise control probably won't work. Either of those likely would cost you a few hundred bucks to replace. And if that's all you need, that hardly seems like imminent doom.

On the other hand, your Subaru is about at the age where we often see catalytic converters failing. If the converter is failing, then you're looking at $1,500 -- plus whatever is wrong with the cruise control (because the catalytic converter won't affect the cruise control).

Incidentally, when a catalytic converter is failing, sometimes the check engine light will come on and go off intermittently, until the efficiency reading is consistently low enough to keep the light on all the time. That may be the "fix itself" miracle you've read about. But eventually, the light will come on and stay on.

So here's what you need to do, Belinda. Take your Outback to your favorite mechanic, and ask him to scan it. When a check engine light comes on, the car's computer stores a code to tell the mechanic what component tripped the light. Isn't that handy?

If it's a sensor or a broken wire, click your heels together and say, "There's no place like home" (isn't Belinda the good witch from "The Wizard of Oz"?).

If it's the catalytic converter, ask the mechanic whether he thinks the rest of the car is in good shape. If it is, and the mileage on the car isn't in the stratosphere, then it's probably worth putting in a new converter and driving it for a few more years.

On the other hand, if he says the failing converter is the best thing on the car, then it's time to look at the 2018s. Good luck, Belinda.

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