P0442 Evap System Small leak

[Fudwamper]

After replacing the gas cap I took my 2002 LW200 into the shop for the P0442 evap system small leak code because I could not pass emissions.

I received the following from a service inspection:
1) "Checked the purge valve for the system and found purge valve get good power and ground, has very little flow through it open or closed.

2)Accessed a line to the vent valve and checked flow found there to be flow even when closed. Unable to isolate vent valve because it is on top of the tank, need to see if it is the valve or a break in the line.

3)Recommend replacement of purge valve and inspect top of tank. "

Ok I am now in a place where I can lift the car and do the work myself. I read this as in both the purge valve and vent valve need to be replaced.

How do you isolate the vent valve? How do you check to see if it is the vent valve?

How do I check the line beside visually? any tips?

[pierrot]

Originally Posted by Fudwamper

After replacing the gas cap I took my 2002 LW200 into the shop for the P0442 evap system small leak code because I could not pass emissions...

...I read this as in both the purge valve and vent valve need to be replaced.

How do you isolate the vent valve? How do you check to see if it is the vent valve?

How do I check the line beside visually? any tips?

Welcome to SaturnFans, Fudwamper! I cannot tell you how to verify proper operation of either valve. I can give you their correct locations.

1) EVAP Vent Solenoid (valve) is at the top of the fuel filler pipe inside the right rear-wheel opening.
2) The EVAP Purge Control Valve (solenoid) is located next to the air cleaner box.

Please look very carefully for cracks, how ever small, in any of the air lines connected to these parts (whether steel, rubber, or plastic). If any are found then replace as necessary.

The FSM (Factory Service Manual) provides instructions to diagnose faults with these components. However, neither you nor I are likely to have the specialty tools required for this (at least I know that I don't have them). Prices for these parts are not expensive. By way of example see the links below.

http://www.rockauto.com/en/catalog/s...+solenoid,4936

https://www.gmpartscenter.net/?p=cat...ge%20Solenoiod

http://www.rockauto.com/en/catalog/s...solenoid,16992

https://www.gmpartscenter.net/?p=cat...ent%20solenoid

[Fudwamper]

Thanks a ton Pierrot,

I remember these pieces when I placed the new fuel pump into it. I probably poke a hole somewhere and ruined the pieces at some point.

I will take a close eye to those hoses, any suggestions for small leak detection.

[fdryer]

Search past threads (one I posted) about P0455, large evap leak. Examine the main fuel pipe and the smaller pipe running alongside it. Mine rusted thru at a midpoint bracket (most likely from salting roads in NYC winters). A small leak became a large leak. Replacing the fuel filler pipe cured the problem and allowed me to examine the vent solenoid since the fuel fill pipe assembly has the evap vent solenoid attached. Its just a box with a foam filter and a 12v solenoid thats stays open for venting like filling the tank. Its powered up to close during evap system testing to seal the fuel system to check for evap system leaks in positive and negative pressure. A simple mouth blow thru should allow air thru and applying 12v should power the solenoid closed to stop air flow. It rarely fails and placed high up next to the fuel pipe and is plumbed into the small steel line running alongside the fuel pipe. Access to the top of the tank will be a bear unless less than 1/4 tank of fuel remains to allow less weight when dropping the tank for inspections.

[Tom Walsh]

Sounds like you may have a leaky gas tank filler neck. Solenoid attaches to it. If you have a friend with a smoke machine, that would pinpoint the leak. They rust up like mad. Don't beat your self up for crushing it, it doesn't take much

[born again]

X3 on the filler neck pipe. Pierrot is in California, and won't have experienced this problem. Mine was purchased used from Florida, but came with a bad purge valve, so I used the old valve.

[born again]

If it is just the smaller steel pipe that is rusted through, you may be able to fix it by cutting out the rusted part and replacing it with rubber hose.

[PLHorton]

In Ca my BAR guy said the evaporation code is the last to set in the ecu. He said to clear the codes and drive until the important codes are set but the evap is not yet set at 25 or 30 miles. Then take it to test. That works for me. The evap isn’t looked at unless code is set.