Evaporative Emissions System (EVAP) Description
Read Some Popular EVAP System Questions And Answers
Read About EVAP System Operation And Description
EVAP System Comments Page 2
1999 Ford Ranger. Can only fill the gas tank very, very slowly. Appears not to be
venting. Where should I look to solve this.
You either have something in the filler neck restricting
the flow of gas, or a bad EVAP vent solenoid. Look down
the filler with a flashlight, if it looks clear, then replace the
solenoid.
1999 Pontiac Grand Am has code P0442 smal leak detected stored in the PCM. I have heard this could be a llose gas cap or a leak in the vent vlave or something like that. Can you give me some help please, thanks.
Yes, P0442 is a small system leak. This could be cuased by a loose gas cap or a bad seal on it, but that will usually cause a check engine light code P0455 large EVAP leak. You can try to replace it and have the codes cleared to see if that repairs the problem. If not, you will have to see a mechanic to run a smoke test to find a small EVAP leak.
Is vacuum the only means by which the PCM will check the integrity of the EVAP
system? Don't certain OEMs use pressure for the PCM to accomplish the same
results?
The PCM cannot create pressure in the system to run a
test. It does look for pressure sometimes to determine if
there is a problem in the EVAP system that normally only
has inches of vacuum.
2010 Chevy Malibu with mileage of 47,000. Took to the dealer with check engine
light. No other symptoms at all, the car runs and drives normally. It returned codes
of p2198 and p1440. Dealer says the canister purge valve and canister assembly
are defective and need replaced to the tune of almost $700. I don't have that kind
of money right now. First question, what are the risks of letting this go for a while
until I get the money? Second question, is this legit, does it really need to be
replaced at all? I don't have to worry about emissions testing in my area.
If you do not have emission testing, then you can without
these repairs.
I have a 97 Nissan Sentra gxe the EVAP vent valve is located near the gas tank
behind the rear driver side reel right? I took it off and cleaned it and found the
solenoid wouldn't activate when i plugged the wire harness back into it. Checked it
with volt meter and was getting 11.5 volts. So i hooked it strait to battery which
gave it 12.5 volts and the solenoid worked. i even blew into one of the hose
openings to be sure no air was slipping thru when i did this. So i reinstalled it but
cut the ground wire from the harness and rapped it around a screw now the vent
valve is getting 12.5v. and activates soon as u turn the key. Seems to be ok but its
getting really hot and i still cant clear the code and check engine light. And i got an
emissions test coming up at the end of the month. Any suggestions would be
greatly appreciated.
What you just did by wrapping that wire around a screw
was complete the ground circuit that the computer is
suppose to control. So, the valve is on all the time. That
is why it is getting hot. The engine light will still be on
because the system is not venting when it is suppose to.
Re-install the wires properly, test for 12 volts in, which
you do have. Then test the other wire for the computer
grounding it when it is suppose to. This would need to be
done with a scanner to turn on the and off the valve. If no
ground, check the wire back to the computer for
continuity. If it OK, then maybe a bad control module.