code P0440 Help!

wold_77 · 02-03-2007, 05:09 PM

I have replaced the gas cap and checked all the lines for leaks. I still get the code P0440 after about a mile or two of driving. Also after I fuel the car it runs very ruff for about a mile or so. I recently changed the fuel filter also was told water might be in the filter causing it to run funny no change was noticed. Any suggestions would help greatly! I have a 1999 Sephia.

1fastkia · 02-04-2007, 08:03 AM

Put some dry gas in and get a new gas cap. the seal might be gone.

wold_77 · 02-05-2007, 10:27 AM

The gas cap was just replaced. Will try some gas additive. I am also thinking about replacing the purge control valve and charcoal canister.

CvGhost · 02-13-2007, 09:55 PM

Well couple of things you might want to check. Check these things
EVAP: Canister purge valve, Canister close valve , Fuel tank pressure sensor, the canister itself and or all fuel lines. If you know what your doin check those items if not ask a good mechianic to check those things.

DrLew · 03-02-2007, 04:44 PM

I have had my 1999 in to the Dealership here to fix my p0440 error code and they were not able to find the problem. They want to try a new computer ($800) (I don't think so) I have checked it out myself and I believe it is the pressure sensor under the rear seat in the top of the gas tank. It is supposed to measure the change of pressure in the tank and if it doesn't, it turns on the check engine light after two driving cycles.

Even my State Government Emissions website posted a possible fix. They think there is liquid gas in the vapor return line (doubtfully) that is keeping the sensor from measuring the change.

I bought a new pressure sensor from the dealership today. ($187.50...ouch) I will post back if it works.

DrLew · 03-02-2007, 08:00 PM

As I suspected, two complete trips so far, still no P0440 error. Nor any other code for that matter....

I will check back in a few days if it comes back, but I suspect it is finally fixed.

Well Just to update this post. I still have not gotten the MIL to turn on again. I have checked regularly since the light was on for soo long (almost 2 years). No more P0440 errors!