Check engine light

[Weirdguy]

Just wondering what a "Evap Emission Ctrl Sys vent valve/solenoid circ error is. The truck is an '06 Sierra with the 5.3.

[00shortbox]

99 times out of a 100 it needs a vent solenoid.

[oleshifty]

check gas cap first...make sure you don't leave car running when you fill up, make sure seal is in good shape/clean.

[GasGuzzler]

Gas cap won't set a vent solenoid code and the OP needs to post the code he has. The VS's do stop up with dirt all the time (as well as the canister) causing P0446. If that's the case you need the updated kit that has a non-filtered VS and a separate filter to mount up front. Or you could get a tune that turns all that off and adds 30 HP for the same price. Your choice.

[Weirdguy]

Gas cap won't set a vent solenoid code and the OP needs to post the code he has. The VS's do stop up with dirt all the time (as well as the canister) causing P0446. If that's the case you need the updated kit that has a non-filtered VS and a separate filter to mount up front. Or you could get a tune that turns all that off and adds 30 HP for the same price. Your choice.

It's not my truck, but I'll ask the owner what the code is.

btw. Would turning that stuff off effect the emissions? If so, how badly would they be effected?

[GasGuzzler]

How badly is a tough question but it's only to do with gas vapors not tailpipe emissions.

[Weirdguy]

The code is a PO449.

[GasGuzzler]

That usually means the vent solenoid itself is open....not clogged with dirt like with P0446.

[Weirdguy]

So it still needs to be replaced?

[GasGuzzler]

Yeah, but just the vent solenoid. You don't need the canister ($197 retail). You will still have to install the long hose and filter as the vent solenoid has a new design.