P0446 Code on Wife's 03 Z71

[BrownSunshine]

New guy here!

So my wife's Tahoe had a Knock Sensor code for awhile and I finally got around to replacing them (dumbest knock sensor location ever). I also replaced the catalytic converters at the same time due to them rattling very bad (car has around 160k on it)

After I replaced the parts, the code disappeared but the car would die at a stop light or idle rough. After a day or two of this, the car started to finally run good but then I got a check engine light again, this time it was the P0446.

Now I have read about issues with this and bulletins for this code, but I'm almost wondering if I cracked the hose that runs next to the intake when I was removing/replacing it.

Or maybe it was just perfect timing and it is something else.

Plan on doing a smoke test on it tomorrow, but does anyone else have any input?

 

[Scottydoggs]

thats a evap code, you sure the purge solenoid is plugged back in?

the code solutions looks like its not getting power. or maybe a cracked line. https://www.obd-codes.com/p0446

 

[BrownSunshine]

I’m positive it’s plugged back in. When I put the intake back on I was having some problems routing the evap line that runs next to the fuel rail. Maybe I cracked that

 

[Rocket Man]

Evap code pointing to the vent solenoid. I had that and it was the vent solenoid, located on the purge canister right in front of the gas tank. It was easy to replace.

 

[Chubbs]

Evap code pointing to the vent solenoid.

^ this.

I also successfully resolved the 0446 'large/gross EVAP leak' with vent valve solenoid R&R

I never experienced symptoms to the degree that OP is but I did get the occasional odor of fuel. If different vent valve doesn't clear up the code, it should be the EVAP purge valve under the engine cover. They are on opposing ends of the same line that delivers the fuel vapors to the engine on PCM demand. I just replaced both of them with junkyard parts. When the replacement purge solenoid didn't do the trick, I went & swapped the vent solenoid at the back of the truck and success.

 

[dwells2010LT]

New here too. Recently I had the pleasure of having my vent valve solenoid go bad. I replaced it and the next time i filled up the light went off and it was back to normal. The very next time i got gas, the engine light came back on. I checked the code and it was a PO442 which was different from the PO449 the first time. Now when I fill up, the gas shoots out of the filler neck when the tank is full. Is my problem still related to the vent valve solenoid or is this something new?

 

[Scottydoggs]

New here too. Recently I had the pleasure of having my vent valve solenoid go bad. I replaced it and the next time i filled up the light went off and it was back to normal. The very next time i got gas, the engine light came back on. I checked the code and it was a PO442 which was different from the PO449 the first time. Now when I fill up, the gas shoots out of the filler neck when the tank is full. Is my problem still related to the vent valve solenoid or is this something new?

ive found when they spit gas back up the filler its the canister tank or solenoid on the tank at fault. the canister tank fills with gas and fails to vent right. or the solenoid is bad.