P0446 Code - 2004 Silverado - Location?

[hppr1234567890]

So what is it that's throwing this code? I was told it was a valve between gas tank and charcoal canister? These are the two things I found that look like they might be what I am after:

 

 

 

 

[hppr1234567890]

Well just an update I pulled everything apart and found some dust, cleaned it all out and replaced the round canister thing with an AC Delco part 214 2149. After a couple days light came back on so I guess it's the fuel tank pressure sensor? Ugh.

[Jsdirt]

Shouldn't be - should be vapor only.

[Duelin]

2004 Chevy Silverado


P0446 V8 5.3


EVAP Canister Vent Blocked

After conditions are met the ECM opens the vent solenoid but the FTP voltage remains high

Probable Cause

Plugged vapor canister
Failed vent solenoid
Pinched or blocked EVAP hose
Failed FTP sensor

[kstruckcountry]

It is probably the round unit in the second picture. It's most likely full of dust. The rectangular canister could be plugged too if you drive on much dirt, so I'd look at it. The "updated" evap vent canister comes with a remote filter that can be put somewhere less dusty.

 

I have never heard of washing the engine causing this problem. The evap valve on top of the engine is really well sealed, and is underneath the plastic cowling on top of the engine. More than likely if the valve was getting fluid in it, it was fuel from topping off the tank. Topping off and dust are not good for the system.

 

Sent from my SM-G920V using Tapatalk

[Jsdirt]

That's why troubleshooting is a better practice than using the "parts cannon".

 

That cannon gets expensive ... and GM loves you for it.

 

There could be a wiring issue to the sensor you just replaced, or another sensor. Always have to verify wiring on these things - GM didn't use the best quality stuff here, IMO. Seems to be a constant source of issues in every system, especially in the salt belt.

[hppr1234567890]

Just a little update...

 

I finally decided to take it to a mechanic & the light turned off when I got there. It smogged just fine.

 

Typical GM gremlin headscratcher.

[Dnt]

well the 2009 had a vent hose that ran all the way up to behind the engine and that is where water entered the system on mine. The new one came with a new vent line with a different end and it was to be rerouted per instruction but I just stuck the new canister on and rolled with it was too hard to get the the hose. Somebody else's problem now all I can tell you is NEVER BUY A USED VEHICLE LMFAO

[Dnt]

Yes that round thing. I replaced mine on my old 2009 the vent line from that valve runs up to the back of the engine and apparently if you pressure wash your engine you can get water into the vent and it runs back into the valve rusts it and locks up the interior of the valve. New valve came with a new vent hose end so it could be rerouted but it was too much trouble so I just stopped washing the engine and BAM good to go for another 50,000 miles till I traded it...... My gripe was that since it had a code my remote start would not work so I HAD to fix it. Seems like Rock Auto had the part for around 40 bucks at the time took like 10 minutes to change it. Good Luck and STOP washing the engine

[hppr1234567890]

OK so the round thing in the 2nd pic on the back of the gas tank is the likely culprit? And if I take it off and disconnect the hoses from it is it full of gas or anything?

[hppr1234567890]

Well I checked the voltage at the solenoid and it seemed OK plus it's been vapor tested by a shop and they didn't find any leaks...what do you suggest?

[Jsdirt]

well the 2009 had a vent hose that ran all the way up to behind the engine and that is where water entered the system on mine. The new one came with a new vent line with a different end and it was to be rerouted per instruction but I just stuck the new canister on and rolled with it was too hard to get the the hose. Somebody else's problem now all I can tell you is NEVER BUY A VEHICLE BUILT AFTER 1995 LMFAO

 

Fixed it for ya.

[kstruckcountry]

well the 2009 had a vent hose that ran all the way up to behind the engine and that is where water entered the system on mine. The new one came with a new vent line with a different end and it was to be rerouted per instruction but I just stuck the new canister on and rolled with it was too hard to get the the hose. Somebody else's problem now all I can tell you is NEVER BUY A USED VEHICLE LMFAO

That's a problem with the line, not washing the engine. Buyer beware

[Jsdirt]

5v reference was good? Ground good? Signal making it to the computer, and if so, the correct signal? Is the PCM grounding the circuit as it should? Is the valve actually closing when commanded to be?

 

I believe the problem lies somewhere in these questions. There is also the possibility that there is a blockage in the vent line somewhere.