Vent Solenoid P0446


silveradofirerescu
12-26-2007, 10:21 PM
Got a code P0446 today and was wondering what could have caused it? I have a 2002 z71 with 5.3. Also where is the vent solenoid located and what does it do? I cannot tell what is wrong with my truck as it runs fine. Thanks!

j cAT
12-28-2007, 10:03 AM
Got a code P0446 today and was wondering what could have caused it? I have a 2002 z71 with 5.3. Also where is the vent solenoid located and what does it do? I cannot tell what is wrong with my truck as it runs fine. Thanks!
this is usually a defective or improperly installed gas cap. but if this is not the problem, evap vacuum lines , defective vapor canister , dtc set off by incorrect gas tank pressure/vacuum. also dirty evap vent valve located at gas tank /canister area. also p0449 is evap vent solenoid dtc..........

Riche
01-02-2008, 05:53 PM
This is just what I would try before replacing the vent solenoid. First I would turn on the ignition, test the 2 wires at the solenoid. One should have 12v the other should be a ground. If you have that then I would try to verify if the solenoid was stuck closed. (I tried unplugging mine and plugging it back in to see if it would make a clicking noise, but I could not here anything.) With out verifying the condition of the solenoid you run the risk of replacing it and the blockage being somewhere else.(they charged me $80 for mine so it is not a cheep part to gamble with) I am not a tech, so take my advice with a grain of salt, I hope this helps.

j cAT
01-02-2008, 06:32 PM
This is just what I would try before replacing the vent solenoid. First I would turn on the ignition, test the 2 wires at the solenoid. One should have 12v the other should be a ground. If you have that then I would try to verify if the solenoid was stuck closed. (I tried unplugging mine and plugging it back in to see if it would make a clicking noise, but I could not here anything.) With out verifying the condition of the solenoid you run the risk of replacing it and the blockage being somewhere else.(they charged me $80 for mine so it is not a cheep part to gamble with) I am not a tech, so take my advice with a grain of salt, I hope this helps.
i was wondering your experience is that p0446 was a stuck closed vent solenoid valve ? i guess that if the solenoid was stuck closed then the gas tank pressure/vacuum would also cause this code .the p0449 is when the pcm does not see that the vent solenoid is connected or improper current flow to coil. But if the valve is plugged or stuck closed then you get p0446?

brian 1
01-02-2008, 07:01 PM
maybe this will help.found this bulletin.vent solenoid on these get dusty and plugged.you have to relocate vent solenoid and replace it.it's outlined in this bulletin.maybe will help in your diag.Subject:DTC P0446 (Restricted/Blocked EVAP Vent Path) Set, Service Engine Soon (SES) Lamp Illuminated (Replace Evaporative Emission (EVAP) Vent Valve Solenoid Assembly with Service Kit) #02-06-04-037C - (04/17/2007)

Models:1999-2007 Chevrolet Silverado (Classic) Models
1999-2007 GMC Sierra (Classic) Models


This bulletin is being revised to update the warranty information to include additional labor time for diagnosis. Please discard Corporate Bulletin Number 02-06-04-037B (Section 06 -- Engine/Propulsion System).
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1962238&psdid=271&evc=sm#ss1-1962238">Condition

Some customers whose vehicles are operated in dusty type environments, such as farming or mining off-road type applications, may comment about the illumination of the instrument panel SES light, with a DTC of P0446 (Restricted/Blocked EVAP Vent Path) being set.
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1962238&psdid=271&evc=sm#ss2-1962238">Cause

Dirt and dust intrusion into the EVAP canister vent hose assembly, resulting in restricted air flow, may cause this condition.
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1962238&psdid=271&evc=sm#ss3-1962238">Correction

After following the Service Information diagnostics for P0446 and determining that the EVAP canister vent valve is the cause of the SES light, replace the existing EVAP canister vent valve assembly with a new assembly. This new assembly is a sealed unit that is designed to be vented through a remote filter box. To ensure correct installation, follow the procedures below.
1999-2003 Model Year (Use Service Kit P/N 19152345)

<LI type=1>Raise the vehicle. Suitably support the vehicle. <LI type=1>Disconnect the EVAP canister vent valve electrical connector, if equipped. <LI type=1>Disengage the two vent valve pipe clips securing the pipe to the underbody. Remove the clips from the underbody and discard. <LI type=1>Disconnect the vent valve pipe at the EVAP canister. <LI type=1>Remove and retain the EVAP canister vent valve bracket mounting bolt. <LI type=1>Remove the complete EVAP canister vent valve assembly with bracket attached and discard.
http://service.gm.com/engif/000/001/848/1848436.gif
http://service.gm.com/tif.gif (http://service.gm.com/servlets/RetrieveTif?pic=1848436)
Important: The new canister vent valve will be installed in a new location, outside of the frame.
<LI type=1>Position and secure the new valve assembly to the frame bracket on the outside of the frame using the existing hole and mounting bolt. Tighten
Tighten the bracket mounting bolt to 12 Nm (106 lb in).
<LI type=1>Connect the vent valve pipe to the EVAP canister. <LI type=1>Install the two vent valve pipe clips into the existing underbody holes. <LI type=1>Connect the EVAP canister vent valve electrical connector, if equipped. <LI type=1>Attach bulk 5/8" heater hose to the vent valve port and secure using a clamp. Run a length as needed along the frame rail routing to the area above the transmission. <LI type=1>Cut the hose to determined length and install the supplied filter box. Secure using a clamp.
http://service.gm.com/engif/000/001/848/1848438.gif
http://service.gm.com/tif.gif (http://service.gm.com/servlets/RetrieveTif?pic=1848438)
<LI type=1>Secure the filter box to the fuel lines above the transmission using a tie strap. The filter box opening should be pointing downward. <LI type=1>Tie strap the hose as needed along the frame rail in order to keep the hose away from pinch-points and heat sources.
Lower the vehicle.2004-2007 Model Year (Use Service Kit P/N 19152349)

<LI type=1>Raise the vehicle. Suitably support the vehicle. <LI type=1>Disconnect the EVAP canister vent valve electrical connector. <LI type=1>Disconnect the canister pipe from the vent valve. <LI type=1>Push in the retainer and remove the existing canister vent valve from the fuel tank clip or mounting bracket. Discard the old valve. <LI type=1>Cut back the existing canister pipe approximately 51 mm (2 in) to remove the quick connect end. <A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1962238&psdid=271&evc=sm#oth4-1962238">Crew Cab Short Box Shown Below, Other Configurations Similar


http://service.gm.com/engif/000/001/848/1848440.gif
http://service.gm.com/tif.gif (http://service.gm.com/servlets/RetrieveTif?pic=1848440)
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1962238&psdid=271&evc=sm#oth5-1962238">Extended Cab Short Box Shown Below, Other Configurations Similar


http://service.gm.com/engif/000/001/848/1848441.gif
http://service.gm.com/tif.gif (http://service.gm.com/servlets/RetrieveTif?pic=1848441)
<LI type=1>Install the new canister vent valve to the fuel tank clip or mounting bracket. <LI type=1>Cut bulk 5/8" heater hose to a length of approximately 76 mm (3 in). Install the hose between the vent valve and the canister pipe and secure using clamps. <LI type=1>Attach bulk 5/8" heater hose to the vent valve port and secure using a clamp. Run a length as needed along the frame rail routing to the area above the transmission. <LI type=1>Cut the hose to determined length and install the supplied filter box. Secure using a clamp.
http://service.gm.com/engif/000/001/848/1848438.gif
http://service.gm.com/tif.gif (http://service.gm.com/servlets/RetrieveTif?pic=1848438)
<LI type=1>Secure the filter box to the fuel lines above the transmission using a tie strap. The filter box opening should be pointing downward. <LI type=1>Connect the EVAP canister vent valve electrical connector. <LI type=1>Tie strap the hose as needed along the frame rail in order to keep the hose away from pinch-points and heat sources.
Lower the vehicle.

j cAT
01-02-2008, 07:59 PM
this is an excellent explanation of this failure great pictures ! thanks

silveradofirerescu
01-03-2008, 10:02 PM
Does anyone have any idea how much this kit costs? Probably couldnt hurt...

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