Purge Valve Solenoid & Vent Valve Solenoid - Help Please [Archive] - GrandAmGT.com Forum

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hooligan
08-10-2011, 12:58 PM
Hi guys,

Can someone fill me in on the differences between these two parts? I have a 1998 Grand Am GT with 140,000 miles that recently threw a trouble code "P0442" when the check engine light came on. I did some searching here and read a few threads regarding these parts and this trouble code, but there seems to be some overlap on what part people are calling what.

First thing I did was replace the gas cap as my stock cap's rubber gasket was looking pretty beat (cracked and original). No dice. Then I checked a few of the vacuum lines from the purge canister in the engine compartment and they appeared to be fine.

I did notice a strong smell of fuel from the passenger side of the car after a walk around, so I think I am going to replace the purge valve solenoid. Is this the one behind the coil packs?

Where is the vent valve solenoid located?

Thanks for the help!

AaronGTR
08-10-2011, 03:44 PM
Never heard of a vent valve solenoid. The 99-05 grand am's have an EVAP system that consists of a line from the fuel tank to the engine with a charcoal canister in it, and up by the engine there is an EVAP soleniod which opens and closes the line to the intake manifold to purge the fuel vapors from the charcoal canister. The manual refers to it as the purge valve.

That code is for the vacuum decay test. Basically a sensor measures the pressure in the tank over time and if it drops too fast the computer thinks there must be a leak in the system letting pressure out. It's basically an emission control to keep fuel vapor from escaping. If it fails the test twice it sets the code. Checking or replacing the gas cap is usually the first thing to check. If that doesn't do it, that means there is a leak somewhere else. Next place to check is the vacuum tubing connecting to the EVAP solenoid on both sides. It's the little black thing on the right rear corner of the intake manifold between the throttle body and the ignition coils, and it has a harness plug on it. Check the plastic tubing and rubber connections for cracking or splitting. They get brittle with heat and age.

Those are the two most common areas of failure. After that you have to start looking at the lines under the car and connections to the fuel tank. Not sure it the set up on the 98 grand am is the same, but I wouldn't think it would be much different. Good luck!

MMGT1
08-10-2011, 05:59 PM
The EVAP canister may have released carbon particles that have damaged the Canister Purge Solenoid Valve. If you are replacing it, make sure you check the canister for carbon or damaged lines. A crack in the canister can result in the code you are seeing, as well as a damaged o-ring or a leak in a fuel line. You need to trace that "smell" as you put it before you go replacing the solenoid.

MMGT1
08-10-2011, 06:03 PM
To add, there is a EVAP service port on the car that you can attach a "smoke machine" that will aid in finding a leak in the EVAP system

hooligan
08-10-2011, 07:35 PM
thanks guys.

i'll pull the canister tomorrow to check for damage before i replace the purge valve solenoid. would a problem with the canister be as obvious as a crack or other sign of physical damage? would there be loose carbon particles in the canister itself?

drakesrevenge
08-12-2011, 01:09 AM
check your fuses first, before you go through all that work

AaronGTR
08-12-2011, 04:29 AM
check your fuses first, before you go through all that work


uh, fuses would have absolutely NOTHING to do with this problem dude. If you look at the code that says it for loss of vacuum in the system. Everything is working, there's just a leak somewhere.

pongagt
11-15-2011, 09:31 PM
I had a P0442 small leak code on my 99 GT and the problem is the vent valve solenoid is cracked. My friend borrowed a smoke machine and he could see smoke coming from the crack when under pressure. I just replaced the same thing on someones 2000 Malibu with a P0440 general Evap code. They are cheap to replace. They seem like a common Evap problem for our cars.

My vent valve is located behind my gas tank and right in front of my rear frame. It is next to the big vapor canister.