P0446 - Evaporative Emission Control System Vent Control Circuit Malfunction.
showed up as a trouble code a pending code and a freeze code.

checked the gas cap, on tight.. o ring looks fine. any ideas?

 

Make sure that all of the hoses to the charcoal canister, fuel tank, etc. are properly installed and fully seated, also make sure that none are bent or kinked...a few different things could give that code...bad EVAP vent valve, fuel tank pressure sensor, even a bad charcoal canister (sometimes they break down internally and the pieces clog up ports)

 

could this have anything to do with the fact that I just installed my Nelson tuned 02' PCM @ 50 miles ago?

 

That shouldn't have anything to do with it, unless there was an internal PCM problem. Anything's possible, but I doubt that the new PCM is at fault. EVAP codes are pretty common with just about every manufacturer...I had a similar code on my wife's Matrix about 6 or so months ago, and was able to figure out that the charcoal cannister was flooded with fuel. I figured out that it was a result of a local gas station squeezing every last drop while trying to round up to the nearest dollar (New Jersey isn't self-serve). I cleared the code and have been lucky so far (knock on wood)

 

cool, thanks man. I appreciate it. I'm going to check it all out friday. I'll post with findings

 

code cleared it self on the drive home today.... I guess mabye it was over filled. Although I never top off.... good riddance........wtfe... thx man. i appreciate it.

 

Had the same code with mine. The dealer cleaned the filler neck to tank connection, $45.00 labor.

 

Cool deal, hope it stays "fixed"

 

So my SES light came on the other day despite the fact that the truck's running strong and so I took it to Auto Bone to have then pull the code and P0446 x 2 is what I got. Any idea what kind of damage to my wallet I can expect when I take it into the stealership if none of the obvious things (loose connections, kinked hoses, etc.) are the culprit?

 

hey I had the same deal P0446 comin up twice on 2002 tahoe. i gas cap but it came back, if i remember correctly it was a bad evap vent solenoid that was failed to open, 50 $ new at dealer, replaced it and it was all good