Dear Car Talk:

Buzz, our 2011 Toyota RAV4, let us down. Following a 65th wedding anniversary celebration, Buzz refused to start. As I beckoned to my favorite nephew with my crooked finger, he came over, smiled, popped the hood and said he would jump-start Buzz. Alas, after three attempts, Buzz did nothing. Favorite Nephew then looked more carefully, popped open a small cover next to the battery, pulled a wrench from his toolbox ... smiled again and announced that he would restart the computer. It worked! He sent me on my 200-mile drive home with the wrench just in case! When I called the Toyota service department the next day, I was told that Favorite Nephew did the right thing. So I reset the clock and radio, and will mail the wrench back to Favorite Nephew -- after I purchase a replacement to carry in the glove box. The question: Is it normal for a car to act like this? Are there precautions I should take, other than purchasing my own wrench that fits? -- Claire

You should consider forcing Favorite Nephew into indentured servitude, Claire. Tell him if he plays his cards right, he might inherit a 2011 RAV4 someday.

I'm actually confused by his use of the phrase "restarting the computer." But here's what I'm guessing happened: The car wouldn't start because there was a loose connection coming off the battery.

There are two cables attached to the battery. One is a ground cable that goes to the chassis, and the other cable goes to the power distribution box. If either cable doesn't have a good, tight connection, the battery's power will be unable to get to the rest of the car. So a jump-start, which just boosts the battery, might not help either.

So, what your favorite nephew probably did was remove the little black plastic cover on the battery terminal and tighten up the loose cable with his wrench. That reconnected the battery to the rest of the car, and everything worked fine.

You had to reset your clock and radio presets because the battery had effectively been disconnected while you were boozing it up at the anniversary party, Claire.

The connection simply may have shaken itself loose over the six years you've been driving the car. Or corrosion may have built up to the point that it was interfering in the transfer of electricity. Or maybe you had the battery changed at some point more recently, and the mechanic just didn't tighten everything up correctly.

In any case, unless the terminals are badly corroded, I doubt you'll need to perform the same procedure again anytime soon. But keep the wrench in your car anyway. Maybe you'll be able to help another damsel in distress in a 2011 RAV4, Claire.

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