Problem With Evap System

I started having problems pumping gas some time ago. I wouldn’t be able to pump more than $1.50 or so at a time without the pump shutting off, though holding the nozzle upside down and pumping that way would get me a bit more in one shot. Then the CEL came on. I have a cheap OBDII reader that allows me to read and erase, so I plugged that in and got a P0442 code - “Evaporative emission system leak detected (small leak)”. The problem has gotten a bit worse since I first learned of it. I can get just under $1 of gas at a time, and if I turn the nozzle upside down now, some gas leaks back out and down the side of the car. (Yes, I’ve stopped pumping gas upside down now lol)

The average price for a smoke test around here seems to be $90-$100. Thought maybe someone here might have a good idea of what’s wrong given the symptom and the code so I could skip the cost of the test and jump to the cost of the fix. I have an emissions test coming up in a couple weeks. I’m not sure I can pass the test with this problem even if I erase the code and drive until the readiness monitors are mostly good.

I’ve been reading up on evap systems, and thought maybe it’s the vent valve? I could probably see a tear in a hose, but can I check to see if a valve is the problem myself?

Try this: disconnect the negative battery cable a couple of hours prior to your test…the longest the better. Usually the CEL will not come back on for a couple of days after that. It works for me! You can also try this fix:

Could you disconnect the hose that goes from the gas tank/filler to the valve, and see if you can then fill the tank normally?

Do not disconnect the battery before your emission test.

Also Note: Disconnecting the battery will NOT allow a vehicle to pass an OBD II plug-in emissions test. It may temporarily turn off the Check Engine light, but this won’t fool the computer at the test lane. When the test computer is plugged into the vehicle diagnostic connector, it will check the PCM to see if all of the OBD II self-diagnostic monitors have run. If all of the monitors have not completed, the vehicle will be rejected at the test lane. You will then have to continue driving your vehicle until all of the self-checks have completed (which may take up to several days). If the Check Engine light does not come back on after all of the self-checks have completed, the vehicle will pass the test. But if there is a problem, the Check Engine light will come on again and the vehicle will fail the test.


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Sorry, I should have mentioned that the CEL turned off a couple weeks ago. The code was still there when I checked this morning though. The CEL does flash when I turn the car on, so I know the bulb didn’t burn out.

Here’s an article about spiders laying egg sacs in the EVAP vent system.

If that happens, the gas tank can’t vent while refueling. And the gas nozzle keeps shutting off.

As to small EVAP leak? Try applying a small amount of petroleum jelly to the seal on the gas cap.

If the Check Engine light turns off, replace the gas cap.