02 Sonata GLS Trouble Code P0442

Anyone else had P0442 come up? I have 112800 miles and this code pop up (scanned by the guys at Autozone). I initially thought it was my gas cap not be tightened until it clicked a few times but I'd already
checked that and my check engine light hasn't gone off since I tightened it. Anyone got any clue? The Autozone guys didn't have the code listed for Hyundai specifically but they are sure it's EVAP related.
- Thee Chicago Wolf [MVP]
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Even if it is the gas cap (and I suspect it is) the lite will not go off until a certain number of drive cycles have been completed. May take a while. Best bet is to have AutoZone turn it off and then see if it comes back on.

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Would disconnecting the battery for a few minutes work too?

- Thee Chicago Wolf [MVP]
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On 4/28/2010 14:53, Thee Chicago Wolf [MVP] wrote:

Yes, but it will erase all settings, and you have to re-train the ECU again.

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Thee Chicago Wolf [MVP] wrote:

    I had this code on my '02 Sonata LX with the 2.7. I replaced the gas cap, no joy. Then my local mechanic told me I needed to replace it with a "real" Hyundai gas cap. They come in packs of two at the dealer, for some reason.
    After many more miles of driving, light comes back on. I finally had the hood open and the sun shone in just right. There was a cracked hose where the pipe to the purge valve is attached to the intake plenum. Fixed that, and no more P0442.
    I was pretty daunted by all the lines everywhere in the diagram, but I got lucky and spotted it without having to bust my butt <g>.
    The sucky thing is that you have to drive the car about 150 miles in various conditions for the purge cycle to run. The autozone scanner will not force the purge cycle, only the dealer one apparently.
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Ok, that's one thing to keep an eye on for sure. I recently went to Autozone and bought a replacement gas cap as it was only around $8. I did a 170 mile trip this weekend and filled the tank up before I went out. There and back the light stayed on. Oddly enough, this morning the light was off when I started my car. I'm going to run the tank near dry and see what happens. I'll try my old gas cap at the next fillup and see if check engine comes back on again. If so, then it'll undoubtedly be the cap. I'll have to try a few more times to be 100% sure.
Just in case, where is this diagram in case I have to go that route? I'm having my mechanic recharge my A/C so he can look at the valve while he's at it to make sure it's still good. Thanks much!
- Thee Chicago Wolf [MVP]
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The miles means little. It has to have a certain number of off and on cycles for the light to reset.
I've not had this yet with a Hyundai, but had it on my Buicks. The first time was after stopping for gas in New Jersey on the way to DC. Got gas, had a meal, got back on the turnpike the the light went on. Car seemed to drive OK, but on a long trip I was concerned. Took a day or so, but then the light went off and I had no idea what the cause was. Meantime I has stopped for gas again the put the cap back on correctly.
Next car was a bit different. I'd stop for gas, drive 1.5 miles to my house and park over night. Next morning, as if by magic at 1.5 miles the light would go on and stay on for a couple of days. Only difference was this car actually had a message of gas cap loose.
After a few times, I found that I was topping the tank too much. After stopping at the auto shut off of the pump, it never happened again.
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Actually, in this case, what needs to occur is that the evaporative system test must run and pass three consecutive times. This has little to do with how far you drive nor how many times the car is started. With Hyundai's Bosch fuel injection systems of the nineties, this test would run the first time the vehicle was stationary (for long enough for the test to complete) after 20 minutes of run time. With the Siemens (V6) or Mitsubishi (4 cyl) system on your vehicle, I don't have the information to know when this occurs. And there's really little need to know, since I can now command the test with the scan tool. The forcing of the test wasn't available on the first Bosch cars to which I referred.
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HT,
It seems to have been the gas cap. After I replaced it, the light went off and has stayed off since. The replacement gas cap also seemed to be a tighter fit as compared to the OEM or maybe the OEM one just wore itself out of spec enough to trigger the light.
- Thee Chicago Wolf [MVP]
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