Car’s computer thinks Mom’s a thief

Dear Car Talk:

When my mother drives her car, the alarm goes off and the theft deterrent light comes on. Then the car will barely run. When this happens, the power steering light, the brake light and even the tire pressure light will come on.

She then has to turn the car off, take the key out, open the door and press the unlock button on the remote to get things working again. After doing that, she can restart the car and it will be alright for a while.

We took it to get checked out and they couldn't figure it out. She really needs your help. Thanks. – Mary

RAY: Well, that's inconvenient, Mary. Her car thinks she's stealing it. How sad. After all these years, it doesn't recognize the hand that fuels it.

It sounds like there’s a problem with the theft deterrent system, also known as the immobilizer. It’s activating while the car is being driven for some reason. And when the immobilizer is activated, it’s putting the car into what’s called “limp home mode.”

Generally, “limp home mode” is engaged by the car’s computer when there’s a danger that driving the car at normal speed will do serious damage to the engine or catalytic converter. It prevents the car from going more than a few miles an hour; enough to let you “limp” off the next exit ramp, or home if it’s nearby.

The fact that she can “reset” the car by using the remote to unlock the doors tells me it’s definitely a problem with the immobilizer. Unfortunately, on modern cars, the immobilizer is built into the car’s computer. So you can’t simply disconnect the alarm system by cutting a wire, like you could in the old days.

That means your dealer is your best bet here. The dealership is most likely to have seen this problem before. And if they haven’t, they’re most likely to know how the system works in your car, and where to start looking. And brace yourself, because it’s not likely to be a simple short in a wire, and may even require a new computer.

In the meantime, tell your mother to stop wearing a ski mask when she gets into her car. That may be confusing things. Good luck.

Hyundai mysteriously missing oil

Dear Car Talk:

I have a 2014 Hyundai Tucson that I bought brand new. It now has 92,000 miles on it. When I went in for my last oil change, I was told there was no oil in the engine. There are no oil spots underneath my car where I park. Where is it going? What should I do? – Maureen

RAY: Misery loves company, Maureen, and the good news is that you have a lot of company. Hyundai had a number of problems with engines from this era. There are quite a few reports of engines seizing up due to lack of oil, and your engine could be one of those.

So what should you do? Well, the first thing to do is not drive another 8,000 miles. Hyundai offered a 10-year, 100,000-mile power train warranty (which applies only to the original owners) on the 2014 Tucson. They’re about to regret that.

As long as you don’t cross that 100,000-mile mark, you’re covered. So start by asking the shop that changed your oil to put something in writing confirming that they found the crank case empty (or very low, which is more likely the case). If they’ve changed your oil regularly in the past, have them mention that, too, so Hyundai can’t blame this on your lack of regular maintenance.

Then drive over to your Hyundai dealer and tell them your mechanic found the crank case empty. They’ll want to look at the car and see if it’s leaking oil. It’s possible, but since you’ve seen no evidence of a leak, it’s more likely that the oil is burning and coming out the exhaust pipe as blue-ish smoke.

They may want to attempt to fix it for you without replacing the engine. That’s fine. But just keep a close eye on your oil, and keep a record of how much oil you add, and at what mileage.

That way, if it’s not fixed, you’ll be able to insist they do more. And as long as the problem has been reported before you cross 100,000 miles, they are obligated to fix it, even if their first (or second or third) attempts fail.

It’s possible that Hyundai will own right up to this and replace your engine the first time you come in. Since they’ve replaced so many engines now, they must know there’s a manufacturing or design problem.

But it’s good to be prepared in case they don’t do the right thing. So keep good records of your oil loss, be firm but polite and, if necessary, if they try to stonewall you and don’t fix the problem, speak to a lawyer.

This is precisely what a warranty is for, Maureen. As long as you didn’t neglect the car or ignore a flashing oil warning light, you’re entitled to have this fixed at no cost to you. Good luck, and let us know what happens.

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