Q: There is something your readers might fail to do when trading in a late model auto. Those with navigation systems probably have their home address programmed as the "Go to Home" address. In addition, many also might have their garage door opener programmed. This could possibly lead to unfettered access to their property. Sellers should make sure their vital information has been deleted.

A: Good advice. I once bought a used vehicle that had the previous owner's telephone contacts. I didn't recognize any of the names as people who owed me money, so I erased them.

It's all downhill from here

Q: I have had several Subaru Outbacks and had been under the impression that the hill descent feature was designed to let the engine do some of the braking and take the load off the brakes. However, I looked at the owner's manual recently (this is something I do every 10 years or so), and, lo and behold, hill descent is a braking feature. Could this cause excess wear and tear?

A: If you have a long descent down a steep mountain road, it could become an issue. But the Subaru hill descent feature is designed for slow-speed, off-road driving. In that situation, there is no worry of the brakes overheating or wearing prematurely.

Tech talk

Q: For us non-engineers, will you please tell us why an electric vehicle can't contribute to its own charging? Solar roof panels? Alternator/generators?

A: Some of that already is happening, although to a limited degree. During braking, the electric drive motors switch to generators to charge the batteries. It is called regenerative braking. Solar panels have been kicked around for years but are not yet mainstream.

Gas cap issues

Q: My 2002 Toyota Corolla workhorse has just over 100,000 miles and still runs like a champ. I have never had any mechanical problems. However, periodically the check engine light comes on because of a problem with the gas cap. The cap is changed or tightened, and the problem goes away until the next time it randomly happens. Is there a permanent fix to this issue? If not, is there a sensing device that I can purchase to assure me that the source of the check engine light is just a loose gas cap? And how can I clear the check engine light without taking the car to the mechanic?

A: Your car already has a sensing device, the check engine light. When you get a chance, check the gas cap. In most cases, the light stops coming on if the problem goes away, as you have discovered by replacing the bad gas cap. If the light doesn't go off, you should be able to clear it by disconnecting the battery temporarily. But in some cars, you also might lose some data, including the radio settings.

Bob Weber is a writer, mechanic and ASE-certified Master Automobile Technician. His writing has appeared in automotive trade publications, Consumer Guide and Consumers Digest. Send automotive questions along with name and town to motormouth.tribune@gmail.com.