So, I made an appointment to bring my Quest in to our dealer after explaining that the light had come on. They wanted a $100 diagnosis charge. But after reading these posts about the gas cap, I simply wiped down the cap and tighten it back on. The light went right off. Needless to say, I cancelled my appointment. But it made me wonder, if this problem is so common and so easy to at least try and fix yourself, how come our dealer didn't suggest it in the first place before having to bring it in and charge me all that money? Okay, I realize that was a rhetorical question.

Had this happen on 2008 Quest SE after only a few thousand miles, dealer said it was the gas cap. After a week the light would go off, and soon after come right back on. We just ignored it like it was an old Ford. Now with 60,000 miles on it, the light hardly ever comes on. It's the crappy gas here in Minnesota. I put new tires and brake pads on last week (-20F in the driveway), other than that no problems.

The dealer I purchased my used 05' Quest from told me that a lot of times when these vans have their service engine light coming on a lot, it's because too much alcohol is getting into the engine because gas is made with 10% ethanol now something about 02 but I dont understand much car lingo. So, he said to try 100% gasoline which I did and voila it went off after a few driving trips. I let it get low again, stopped at a Shell and put 10% ethanol gas in it since that is all they have. Within two days it was back on again. Worth a shot.

Hi I have agreed with you that basic car parts are up to date and managed in our cars.

Today, just about two weeks after the dealer reset and supposedly solved my "Service Engine Soon" problem, the problem returned. I have been meticulously careful to make sure that the gas cap is properly seated and tightened after a fillup, so I am sure the problem is not mine (I own another Nissan and have never had this problem, nor have I had it with any other car that I've owned in the past forty years, so I don't believe that I've suddenly lost the ability to replace the gas filler cap.)

Back to the dealer tomorrow to see what's causing the problem, since their first diagnosis was clearly incorrect.

The dealer said that the problem was an improperly seated gas cap; it was supposedly caused by some sort of grit on the rim that stopped the gas cap from forming a proper vacuum seal. I was baffled as to how (a) a car that is kept in the garage except when driven around town could have this problem,(b) how I could have such a problem with this car when it's never occurred with any of the two-dozen-plus cars I've owned over the years, and (c) why the car doesn't give something more informative than a generic "service engine soon" light.

Either way, the dealer covered it under the warranty and it took only about fifteen minutes, so I couldn't complain about the service aspect of the whole deal!

Hey, you did much better than me. I have a 2009 Quest bought on 1/21/09; it has 4475 miles on it, and today I got the "Service Engine Soon" message. No problem with the gas cap, which is a frequent culprit, so I guess it's in to the dealer tomorrow.

I love the van when it works, but this is my third annoyance so far (first, the iPod connector can't be advanced from the steering wheel controls, even though it's supposed to according to the instructions; second, the plastic pins holding the mirror hinges onto the sun visors have broken off; and now this).

Local auto part dealers like Auto Zone can read the codes.

i had to change my alt. last week end cause of cracks and i had bought the power steering belt just in case i found any cracks which i didn't but i figured i might as well change it now so that i don't have to deal with it later.any help would be helpful