I drive a 03 Silverado 1500 5.3l and it keeps throwing the code P0446. I have my own code reader and whenever I clear the code it will reappear in a day or two. Our local Chevy dealership replaced the canister and rerouted the intake line to the engine bay so it wouldn't get plugged with dirt. Code freeze frame is always lower RPM range 1500-2000 and under 55 mph.


Do any of you have information why this code is still reappearing after the dealership fixed it or is this an electrical issue? Anything will help Thanks

 

Sounds like the dealer threw a part on it... I dont have the code descritpion and diag info infront of me but... Iirc that usually points to a purge valve issue

 

Is this going to ruin my fuel milage? I only get 14 now and used to get 16 but ive also put a full front ranchhand. Ill probably replace the purge valve but I didn't know if there were some voltage test I could take to find if it was electrical or not?

 

Gimme a few i can look up diag info

 

From what I found, they say to check voltage at vent valve and if it good then power probe and make sure the solenoid clicks and is operational. Ill have to pull the truck into the shop tomorrow and get it cleaned up but I'm going to replace the fuel cap also just to eliminate one problem and not have the big WHAT IF

 

Heres the flow chart for it.....



If the dealer replaced the canister the vent valve and the vent line, begins to lean towrds purge valve or fuel tank pressure sensor

 

Better shot of first page

 

I think I understand how the whole system works now based of youtube videos and how to test each component. Ill see what I can get figured out the next week or so. Thanks for the help!!

 

No problem.... Post back withwhat you find