02 Sonata GLS Trouble Code P0442

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.

Would disconnecting the battery for a few minutes work too?


- Thee Chicago Wolf [MVP]

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.

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.

--
PB
"I suspect you're an arrogant little pissant who grew up in the
Red Bull generation." - CJW

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]

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.

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.

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]