Dear Srikant: No, there’s no law against not driving much, Srikant. In fact, they should give out medals for it.
Here’s what’s going on. Emissions and smog tests these days are performed by the car’s own computer. Your car’s computer is constantly analyzing your exhaust. Kind of like my wife analyzes my exhaust — then flees the room.
Anyway, the computer analyzes the stuff in your tailpipe to see how well your engine is burning its fuel. With that information, it constantly makes adjustments to the fuel and air inputs to keep pollution low.
Since your computer is collecting all of this information anyway, when you go in for an emissions test, the mechanic simply plugs his scan tool into a port on your car and asks for the data.
The computer then reports how much carbon monoxide, carbon dioxide, unburned fuel and nitrous oxides your engine is producing. But before it will even issue the report, the computer performs a “readiness test.” The readiness test is all about your fuel system pressure.
Unless the computer can verify that your fuel system is able to reach full pressure and stay there for a sufficient number of miles, it won’t allow the mechanic to even run the test. And that’s what happened to you, Srikant.
While you can fail the readiness test because of an actual leak (or a loose gas cap), it’s more often caused by not enough driving. That’s what your mechanic thinks it is, and he’s probably right.
So, here’s the solution: Fill up the tank, and make sure the gas cap is properly secured. Then pick a nice restaurant about 40 or 50 miles from home. Take your wife there and have a wonderful lunch.
Get a small box of pastries to go, drive right back to the inspection shop, give the pastries to the mechanic and ask for another test. With 80-100 miles driven on the same tank of gas over a short period of time, you should pass with flying colors, Srikant. The pastries are just an insurance policy.
And if it works, call the restaurant and make another reservation for the same day next year.
Dear Car Talk: I recently purchased a 2013 Toyota RAV4 LE. After a few days of in-town driving, it began to make a high-pitched whining sound from the back end — definitely not coming from inside the car.
It doesn’t happen reliably, though when it does, it tends to begin after I’ve been on the road for 20 minutes or so. When I brake, the noise stops, then begins again when I let off the brake. Hitting a pothole once also made it stop mid-whine.
Another thing I noticed is that the sound doesn’t happen when the roads are wet, though this could be just coincidence. It’s anybody’s guess when it may happen, which has made it hard to convince my mechanic that it’s happening at all!
I’m hoping you, in all your wisdom, can tell me what it is. Thank you! — Charmon
Dear Charmon: It sounds like you may have a sticky brake caliper, Charmon. When you step on the brake pedal, the caliper squeezes the brake pads around the brake rotor — slowing the wheel.
If the caliper is old and sticky, though, it may not release quickly, or completely. So even though you’d taken your foot off the brake pedal, the pads may still be touching the rotor a little bit. And when the pads are just barely touching the rotor, they tend to vibrate, and that’s the noise.
If you move them one way or the other — either press the pads harder against the rotor, or move them fully away, the noise will stop. That’s why stepping on the brakes brings a temporary quiet. When you hit the pothole, it probably jolted the caliper to release the pads. And when it’s raining, the water acts like a lubricant and prevents the pads from vibrating and making noise.
So, it all makes sense, Charmon. Ask your mechanic to check both rear calipers. I think at least one is sticking and needs to be cleaned and greased. And get it done before it binds up completely and chews up your pads and rotor, too.
Got a question about cars? Write to Ray in care of King Features, 628 Virginia Drive, Orlando, FL 32803, or email by visiting the Car Talk website at www.cartalk.com.
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