See more of the story

Q: My 2006 Corvette key fobs work in every way except to start the car in the normal way. I have followed directions to "reprogram" the original key fobs with no success. Shortly after I purchased the car I started getting "no key fobs detected" on the driver information center panel. The vehicle starts when the fob is in the holder located in the glove box. When I follow reprogramming directions the only thing that happens is the fobs become totally inoperative. To fix this I disconnect the battery and they work, except to start the car the way it is designed. The local dealer tried twice with no luck. Most say the remote control door lock receiver (RCDLR) would not be the problem if it starts with the fob in the glove box. Hope you can find an answer.

A: My ALLDATA automotive database pulled up GM service bulletin PIC5961 that addresses this exact issue. It identifies a transistor in the RCDLR as the likely cause. To confirm this is the problem, sit in the vehicle with a known good fob — not in the glove box holder — and press the start button. If you hear only one click rather than several clicks, that pesky transistor in the RCDLR is misbehaving. The solution is to replace the RCDLR located above the radio behind the trim on the right side.

Q: I need help diagnosing a problem with flickering dash and headlights on my 2005 Dodge Grand Caravan with 150,000 miles on it. The problem first occurred last fall. I had the alternator replaced, which appeared to fix the problem. A few days ago the flickering started again. In both instances the problem started when the weather became colder. The battery is a year old.

A: Operating the heater blower motor, lighting system and rear window defroster during cold weather increases electrical demand from the battery and charging system. Some voltage fluctuation — the cause of the flickering — at low engine speeds with heavy electrical loads is not abnormal.

Having replaced the alternator may not have addressed the issue. The electronic voltage regulator (EVR) is an integral part of the powertrain control module and is not a separate component. Alternator output is controlled by the EVR monitoring voltage and regulating the alternator's field winding up to 250 times per second to reach a calculated target voltage. Any increased resistance in the charging system — battery, alternator or chassis ground connections — can cause voltage fluctuations. With an 11-year-old vehicle with that many miles on it, I'd start by cleaning and freshening any and all connections in the charging circuit.

But as long as the battery stays charged, the issue is relatively minor.

Q: I have a 2005 Buick LeSabre with almost 99,000 miles. The service engine light came on about a month ago. I cleaned up around the gas filler neck and put the cap back on again and the light went off after a few starts. Within a couple of weeks the light reappeared and I brought the car to several auto parts stores and had a free analysis done, both of which came back with a code of P0171. A Buick dealer came up with the same code, then removed the code and told me to drive it until it starts to run rough and then bring it back in. A family member recommended a friend that runs a car repair service shop. He changed the mass air flow sensor and sent me on my way. Two days later the service light reappeared again. Do you have any good ideas what is wrong?

A: The P0170 fault code is triggered when the fuel/air mixture is too lean on cylinder bank 1 of the V6 engine. Possible causes include a vacuum leak, faulty fuel injector or an incorrect signal from one of the oxygen sensors on that bank.